Ursa
* Ursa has no sustained AoE to deal with illusions, it becomes worse since Phantom Lancer can create more illusions in a matter of seconds.
* 
Diffusal Blade can be used to drain Ursa mana. This is a standard item for Phantom Lancer in every match.
* 
Doppelganger applies basic dispel on Phantom Lancer, which will remove the slow from Earthshock. It also resets fights with more illusions, making hard for Ursa to hit the real Phantom Lancer.
* 
Manta Style creates two more illusions and also applies a basic dispel, further complicating the problem for Ursa to deal with.
Slark
* Slark has no sustained AoE to fight off Phantom Lancer's illusions as they continually spawn.
* Spirit Lance can give vision of Slark by spawning an illusion, making it harder for him to juke and gain the passive bonus from 
Shadow Dance.
* 
Phantom Rush helps Phantom Lancer chase down Slark if he tries to escape with 
Pounce.
Additional:
* Slark has no sustained AoE damage to deal with a lot of Phantom Lancer's illusions.
* Doppelganger lets Phantom Lancer dodge Dark Pact and Pounce and partially wastes the duration of Shadow Dance.
* 
Spirit Lance can give vision of Slark via spawning an illusion, making it harder for him to juke and gain the passive bonus from Shadow Dance.
* Phantom Rush helps Phantom Lancer chase down Slark when he jumps away with Pounce.
Ursa
* Heroes who rely strongly on melee physical damage will fare badly against Omniknight's Guardian Angel: 
Phantom Assassin, 
Juggernaut, 
Dragon Knight, 
Lycan, 
Ursa, 
Troll Warlord
Slark
* Slark's dependence on Pounce and close range makes him very easy to hit with 
Purification and 
Hammer of Purity.
* Slark's damage, even with a high count of Essence Shift stacks, is easily negated by Omniknight's heals and 
Guardian Angel.
Ursa
* Ursa struggles against heroes with strong (and especially undispellable) disables (
Disruptor, 
Puck, 
Shadow Demon, 
Outworld Destroyer and etc).
Slark
* Outworld Destroyer can disrupt Slark's attacks with 
Astral Imprisonment either by banishing Slark or his target.
* Slark's low heathpool means he will die quickly to 
Arcane Orb if he is directly attacked by Outworld Destroyer
* Slark has low intelligence gain, making him easy to finish with 
Sanity's Eclipse if he tries to run with Shadow Dance
Additional:
* Arcane Orb deals pure damage, which ignores the armor granted from permanent agility stacks.
* Astral Imprisonment can disrupt any Pounce attempt by banishing the leashed ally.
* Slark's low mana pool makes him more susceptible to Sanity's Eclipse.
Ursa
* 
Viper Strike is a strong and breaks Fury Swipes, undispellable slow, making it much easier to kite Ursa for everyone.
Slark
* Heroes with Break abilities will prevent Slark from regenerating and gaining Essence Shift stacks: 
Viper, Shadow Demon, etc.
Additional:
* Viper Strike can disable 
Essence Shift and the regeneration aspect of Shadow Dance.
* 
Dark Pact doesn't mean a lot against Viper's ubiquitous slows.
* Viper becomes a relevant presence in team fights before Slark can procure his standard items (e.g. 
Shadow Blade).
Ursa
* Ursa struggles against heroes with strong (and especially undispellable) disables (Disruptor, Puck, Shadow Demon, Outworld Destroyer and etc).
Slark
* Thunder Strike provides vision on him while Slark is invisible.
* Glimpse's range at lvl 3-4 is more than enough to pull him back to a favorable position for your team to group up and kill him.
* Even though he is capable of picking you off and deal enough damage to kill you, Slark will be literally sticking his neck out, since jumping on Disruptor means being on his battleground.
* AoE silence and the ability to mute Black King Bar is deadly to Slark at all stages of the game.
Additional:
* 
Static Storm and 
Kinetic Field locks down Slark, as he cannot use Dark Pact to dispel any disables, or Pounce out while silenced.
* 
Glimpse puts an end to any attempts at ganking Disruptor or his allies, and also negates Slark's mobility by bringing him back into the fight if he tries to escape with Pounce.
Ursa
* Slardar is one of the few meele heroes who can lane against Ursa in the early game, out harassing him with Bash of the Deep, and running away from a bad engagement with Guardian Sprint
* Corrosize Haze can force Ursa to cast 
Enrage defensively instead of offensively
* With Corrosize Haze, Slardar's team can quickly dispatch of Roshan, denying one of Ursa's greatest advantages
Slark
* 
Slardar's level 25 talent makes 
Corrosive Haze undispellable, thus providing his allies vision of Slark.
Ursa
* Heroes who rely heavily on melee attacks and lack early spell immunity are easily blocked and interrupted by Ink Swell: Lycan, Ursa, Troll Warlord.
Slark
* 
Phantom's Embrace cannot be dispelled by Slark's Dark Pact, and will cause him to suffer damage if he doesn't kill Phantom fast enough.
* 
Soulbind also cannot be dispelled by Slark's Dark Pact, and will cause Slark to suffer from a single-targeted ability used on his ally that is also affected by it.
Ursa
* Melee carries such as 
Sven, Ursa or 
Lifestealer can be slowed and easily kited with Demonic Purge.
Additional:
* Shadow Demon's 
Demonic Purge renders Ursa useless even through 
Black King Bar as it slows him, continually purges his Overpower charges and can not be dispelled by Ursa's Enrage.
* 
Disruption is a good way to save teammates against Ursa. Disrupting Ursa is also a good way to kite him, as it can not be dispelled by Enrage.
Slark
* Heroes that lose a great amount of damage output and become less threatening: Phantom Assassin, Sven, 
Slark, 
Phantom Lancer.
* Once you have an 
Aghanim's Scepter, Shadow Demon instantly reaches a new power spike and becomes a counter for a variety of heroes that have strong passives.
* Heroes that lose a great amount of their tankiness and become easier to finish off: 
Bristleback, 
Spectre, Phantom Assassin, 
Enchantress, Dragon Knight.
* Heroes that lose a great amount of damage output and become less threatening: Phantom Assassin, Sven, Slark, Phantom Lancer.
* You can always stack camps and farm the scepter with Shadow Poison.
Slark
* Natural Order aura prevents Slark from gaining armor from the agility stolen with Essence Shift.
* Echo Stomp and Earth Splitter can hit Slark through his Shadow Dance ultimate.
* Slark's stats gain is relatively low compared to most agility carries making him quite squishy without his agility-based armor.
Ursa
* Heroes with weaker mobility will struggle to keep up with Night Stalker: 
Gyrocopter, Ursa, 
Drow Ranger
Slark
* With Dark Ascension he can keep vision on Slark, disabling his Shadow Dance regeneration.
* Night Stalker is very fast so without the Pounce in lane, he can simply out distance him during the night.
* Slark is matched in night vision by only a few heroes, Night Stalker happens to be one of them.
Ursa
* Heroes with stronger lane presence that can threaten to kill him: 
Batrider, Juggernaut, Ursa, 
Monkey King, 
Razor.
Slark
* Bloodseeker is one of the hardest counters to Slark.Thirst prevents Slark from healing in lane with Shadow Dance and may set him up for a kill while in the jungle,or retreating.
* Rupture will deal damage during Pounce.
* Dark Pact cannot dispel Rupture, preventing Slark from escaping ganks.
Additional:
* 
Thirst stops Shadow Dance's passive health regeneration if Slark's current health is below the Thirst's visibility threshold.
* 
Rupture effectively diminishes Slark's mobility in battle, leaving him susceptible to AoE stuns or forcing to teleport out of the fight.
Ursa
* Heroes that rely on slows to get kills: Lifestealer, 
Night Stalker, Ursa, Phantom Assassin, 
Terrorblade.
Slark
* Slark will have a hard time killing Sand King because of the survivability he gets from Burrowstrike and Sand Storm.
* Shadow Dance, which usually allows Slark to survive fights, is ineffective against Sand King's AoE damage.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: 
Anti-Mage, 
Earth Spirit, 
Faceless Void, 
Magnus, 
Mirana, Monkey King, 
Morphling, 
Pangolier, Phantom Assassin, 
Phoenix, Puck, 
Queen of Pain, 
Riki, 
Sand King, 
Spirit Breaker, 
Timbersaw, 
Tusk.
Ursa
* 
The swarm beetle can waste Ursa's 
Overpower attacks.
* Ursa has no inherent way of disabling a slippery Weaver by preventing him from 
Shukuchiing or 
Time Lapseing away, as the slow from Earthshock is useless against Shukuchi's haste effect.
Additional:
* 
Earthshock's slow is ignored by Shukuchi.
* Ursa can be kited with Shukuchi and his burst damage will be negated with Time Lapse as long as Weaver survives it.
* The Swarm breaks Ursa's 
Blink Dagger, forcing him to deal with the beetles.
Ursa
* If Ursa uses Enrage Brewmaster can use Cyclone to render him harmless during his ultimate.
* Brewmaster has two spells to slow down Ursa, allowing his team to kite around him easily.
Slark
* Dark Pact, Shadow Dance and 
Depth Shroud will do nothing against Onslaught and Trample, as they are both ground area-of-effect spells.
* Primal Beast has a gigantic hitbox, which could be difficult for Slark to escape with Pounce should Primal Beast choose to block him. Pounce also does not completely prevent Primal Beast from trampling offensively, as he still has some room to move.
* Primal Beast has a huge health pool making it difficult to shed it with Essence Shift and may allow Primal Beast to build Uproar stacks against him very rapidly.
* If Primal Beast buys an Aghanim's Scepter he can also break Essence Shift from working on attacks which is a big part of Slark's damage output.
Slark
* Though Slark's large damage output is most certainly a concern for the squishy Crystal Maiden, she does perform fairly well against him when coupled with aid from her team.
* Slark has no innate way to cancel Freezing Field, but the common purchase of 
Skull Basher does make Slark a substantially greater threat to Crystal Maiden as the game progresses.
* Freezing Field can still hit Slark while he is under the effect of Shadow Dance, and for the early and mid game, the damage output of Crystal Maiden's ultimate outscales Slark's passive regeneration, making a quick use of Freezing Field as soon as Slark uses Shadow Dance a great way to combat him.
* Crystal Maiden's Frostbite and Crystal Nova are helpful in disabling and slowing the slippery Slark so he can be killed by her teammates.
Ursa
* Melee heroes that get kited easily have hard times dealing with Puck without any lockdowns, as Puck is one of the most mobile heroes. Heroes like Sven, Lifestealer, Ursa and 
Alchemist may have problems to get to Puck without proper initiation items. They also lack reliable lockdowns, as their disables are easily avoidable for Puck, or are just a soft disable.
Slark
* 
Illusory Orb and 
Phase Shift allows Puck to avoid most ganking attempts.
* 
Waning Rift and 
Dream Coil makes it very hard for Slark to escape bad situations.
* Puck's abilities used together also deals significant magical nuke damage, none of which are targeted and thus cannot be avoided by Shadow Dance.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Ursa
* 
Doom makes Ursa less disruptive, and it cannot be dispelled with Enrage upgraded with Aghanim's Scepter.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: 
Silencer, 
Death Prophet, Puck, 
Doom.
Ursa
* High health heroes (
Axe, Doom) fall fast with Fury Swipes stacks.
Slark
* Slark's low health and reliance on high built armor from Essence Shift makes him susceptible to Muerta's 
Pierce the Veil.
* Muerta cannot be attacked by Slark's physical attacks and Essence Shift during Pierce the Veil.
* Muerta's 
Dead Shot and 
The Calling can hit Slark even while hidden with Shadow Dance.
Slark
* Heroes that can deny Slark early kills will prevent him from snowballing: 
Dazzle, 
Abaddon.
Slark
* Heroes who cannot prevent Sven from killing supports will always be at a disadvantage in fights such as 
Lina, Slark and 
Zeus.
Ursa
* With Aghanim's Scepter, Broodmother will gain access to 
Spinner's Snare, which will allow her to create invisible lines on her webs from 
Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, 
Nyx Assassin, Mirana, 
Bounty Hunter, 
Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, 
Nature's Prophet, 
Enigma, 
Void Spirit, Magnus etc.
Ursa
* Bane can use 
Nightmare and 
Fiend's Grip to lock down Ursa early game and in team fights, forcing Ursa to buy a Black King Bar and making him very vulnerable to being kited once his Black King Bar is down to 6 seconds.
* Overall, Bane's potent disables force Ursa to build more defensive items and play more defensively in general.
Slark
* Low-health, normally mobile carries who rely entirely on raw attack damage are vulnerable to Bane's nukes and disables: Anti-Mage, 
Clinkz, Drow Ranger, Faceless Void, Gyrocopter, Juggernaut, 
Meepo, Mirana, Monkey King, Morphling, Phantom Assassin, Phantom Lancer, Riki, 
Shadow Fiend, Slark, 
Sniper, Terrorblade, Troll Warlord, 
Weaver.
Slark
* Dark Pact can dispel Enfeeble, as well as Nightmare and Fiend's Grip when timed correctly.
* Shadow Dance can protect Slark from Bane's single-target abilities.
Slark
* Slark's Dark Pact and Pounce can deny only one Earthbind and Poof can penetrate Shadow Dance if he doesn't build Black King Bar.
Additional:
* 
Earthbind and 
Poof will still hit Slark in Shadow Dance.
* Dark Pact can only remove one Earthbind.
* 
Ransack will still affect Slark, even if he has a Black King Bar.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: Silencer, Death Prophet, Puck, Doom.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, 
Jakiro, 
Underlord, 
Leshrac, 
Dark Seer, 
Earthshaker, Timbersaw, 
Crystal Maiden.
Slark
* Heroes like Slark, 
Witch Doctor and others also tend to suffer in Ice Blast's heal denial.
Additional:
* 
Ice Blast stops Shadow Dance's passive health regeneration, even when Slark is not in vision.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Ursa
* Storm Spirit can steal 
Aegis of the Immortal during Roshan attempts through the Pit, because of his 
Ball Lightning.
* Ursa has no way to catch a slippery Storm Spirit, as Earthshock's slow will do nothing to stop Storm Spirit from using Ball Lightning.
Slark
* Heroes that rely on their high mobility such as Queen of Pain, Slark and Weaver can be constantly engaged against due to your excellent ability to chase over any terrain. Make sure you carry true sight items (such as 
Dust of Appearance or 
Gem of True Sight) for invisible heroes that could potentially escape your clutches.
Slark
* Pounce's leash prevents Storm Spirit from using Ball Lightning, making it hard for Storm Spirit to escape a gank from Slark.
* Dark Pact can dispel 
Orchid Malevolence's Soul Burn.
Ursa
* Lion has two low cast point disables (
Hex and 
Earth Spike) to control Ursa before he buys a Black King Bar.
* Hex is one of the few abilities that cannot be dispelled even with an Aghanim's Scepter upgraded Enrage.
* Lion can control Ursa's low mana pool via 
Mana Drain.
Slark
* Heroes with heavy magical nukes will take advantage of Slark's poor HP or force him to use Shadow Dance early: Lina, 
Lion, Zeus
Slark
* Lion's lack of escapes gives Slark easier time to catch him through Pounce.
* Shadow Dance gives Slark the advantage of being untargetable, nullifying single target abilities (such as non-upgraded Hex, Mana Drain and 
Finger of Death).
* Dark Pact applies multiple instances of strong dispel on Slark, which is strong against any of Lion's disables.
* Lion's low health pool and low armor make him extremely vulnerable to Slark's damage output.
Slark
* Heroes that can deny Slark early kills will prevent him from snowballing: Dazzle, Abaddon.
Slark
* 
Ensnare prevents using any kind of movement abiilties, Making Naga Siren good against heroes who rely on gap-closing abilities to escape: Phantom Assassin, Magnus, Slark, Riki, Faceless Void, 
Storm Spirit.
Ursa
* Riki can detect early Roshan attempts because of Cloak and Dagger if he frequently checks the Pit.
* Ursa cannot Enrage when in Smoke Screen (Black King Bar will help though).
* Even if Ursa gets vision over him, Riki can Blink Strike away or use Tricks of the Trade after Ursa's initiation to avoid all 
Fury Swipes damage until Earthshock's slow is gone.
Additional:
* Riki can detect early Roshan attempts because of 
Cloak and Dagger if he frequently checks the Pit.
* Ursa cannot Enrage when caught in 
Smoke Screen and will miss his attacks (although Black King Bar will help with this issue).
* Even if Ursa gets vision over him and initiates with Earthshock, Riki can 
Blink Strike away or use 
Tricks of the Trade after Ursa's initiation to avoid Fury Swipes' damage until Earthshock's slow is gone.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Both Scream of Pain and Sonic Wave should hit Slark during his Shadow Dance.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Time Dilation while Dark Pact and Pounce are on cooldown will make these abilities unusable for a long time, reducing his escape potential. However, Time Dilation is dispellable with Dark Pact so it needs to be timed well.
* Chronosphere will not reveal Slark during Shadow Dance but covers the whole duration of Shadow Dance making him unable to use it to attack or escape. Slark still receives the regeneration benefit from Shadow Dance.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Ursa
* Lycan's ultimate makes him immune to slows from Ursa's Earthshock as well as allowing him to outmaneuver Ursa during Enrage. Lycan can also easily chase down Ursa while shapeshifted, should Ursa try to flee.
Slark
* Lycan cannot escape from a Pounce even if he uses 
Shapeshift, and has no disabling abilities to stop Slark.
Slark
* 
Toss and 
Avalanche deals heavy damage to Slark in the early game, making Tiny a very dangerous target to gank.
* Tiny has 0 agility, which means Slark's Essence Shift permanent agility steal does not do much against him.
Ursa
* Due to Tiny's non-existent agility gain, high physical damage heroes are more effective against him (Clinkz, Templar Assassin, Ursa, 
Wraith King etc).
Slark
* Bulwark blocks much of Slark's basic attack damage, even during Shadow Dance.
* Slark finds it very difficult to have a good early/mid game when pressured in the early game by Spear of Mars and God's Rebuke.
* Spear of Mars and God's Rebuke can hit Slark through Shadow Dance and Depth Shroud.
* Should Pounce be on cooldown, Slark is very vulnerable inside Arena of Blood.
Ursa
* Ursa is a special mention because despite Bulwark diminishing most of the damage Ursa does, he is quite durable, especially with Enrage, discouraging the aggressive all-in playstyle of Mars; Ursa can simply not target Mars.
Ursa
* Enchant can dispel Overpower.
* Enchant's slow can help kite Ursa in fights and also in lane.
* Enchantress can out harass Ursa in lane by using her long attack range and Untouchable, as well as out sustaining him with Nature's Attendants.
Slark
* Heroes that can jump on her: Slark, Queen of Pain, Anti-Mage
Ursa
* Primal Roar and the slow from Boars makes kiting Ursa very easy.
Slark
* Heroes with strong dispels can remove Primal Roar's stun: Abaddon, Slark, 
Oracle.
Ursa
* Enrage with Aghanim's Scepter can dispel Flaming Lasso.
Slark
* Dark Pact can dispel Flaming Lasso if is used in anticipation, but a Blink initiation from fog can catch the Slark off guard.
* Slark can also take off any Sticky Napalm stacks with Dark Pact in lane.
Additional:
* Shadow Dance's passive can inform Slark when he's under enemy vision, meaning it'll be very hard to catch Slark off-guard with 
Flaming Lasso.
* Flaming Lasso is dispelled by Dark Pact. Its casting can be prevented with Shadow Dance or Depth Shroud (it requires 
Aghanim's Shard).
Ursa
* Low armor and lack of escape makes Pudge vulnerable to Ursa, specially when he gets his Blink Dagger.
* If Pudge lands a 
Meat Hook on Ursa, Ursa can simply face Pudge head on provided he can burst him down before any follow up disables.
* Enrage's Aghanim's Scepter upgrade allows Ursa to dispel Pudge's 
Dismember.
Slark
* Dark Pact dispels Dismember if timed correctly.
* Pounce allows Slark to escape Pudge's Rot once Dismember is over, and allows him to dodge hooks.
* Shadow Dance hides Slark and grants him a high degree of mobility, which can make him a difficult target to hook and also protects him from Pudge's Dismember (including allies with an Aghanim's Shard).
Ursa
* Fury Swipes will keep stacking on Tidehunter since it cannot be dispelled by Kraken Shell and its bonus damage cannot be reduced by Anchor Smash.
* Enrage dispels the slow from Gush, and if upgraded with Aghanim's Scepter, can even dispel Ravage's stun.
Slark
* Dark Pact dispels debuffs from Gush, Anchor Smash and even Ravage if timed correctly.
* Kraken Shell cannot restore attributes stolen by Essence Shift or dispel the leash if he gets Pounced.
Ursa
* Chemical Rage will rarely save Alchemist against Ursa's Fury Swipes.
* Enrage allows Ursa to both be a threat to Alchemist and avoid his over time damage.
Slark
* Shadow Dance allows Slark to not be targeted by Unstable Concoction, making Alchemist stun himself and making himself vulnerable to the enemy.
* Dark Pact also allows him to just purge off the stun if timed correctly.
* Essence Shift will steal stats over long durations at a time should Alchemist lack the damage to kill Slark.
Ursa
* Even though Ursa is a hero who relies on direct attacks to be effective, Fury Swipes does not work on allies if Ursa is affected by Winter's Curse, mitigating a majority of Ursa's damage. In addition, Ursa's unimpressive attack speed and attack damage without Overpower and Fury Swipes means that he deals little to no damage to allies during Winter's Curse.
* Aghanim's Scepter upgraded Enrage allows Ursa to survive Winter Wyvern's initiation with Winter's Curse.
Slark
* Arctic Burn and Splinter Blast's debuffs are can be dispelled with with Dark Pact. Arctic Burn also cannot be used to escape against Pounce.
* Even though Cold Embrace can protect it's owner from Slark's direct attacks, Slark can still gain Essence Shift stacks from attacking heroes affected by it.
* However, Essence Shift works against allies, and Slark's low health pool means that if he's the target for Winter's Curse, he will go down very quickly as Winter's Curse cannot be dispelled at all.
Ursa
* Ursa's status resistance from Enrage reduces duration of Medusa's Stone Gaze.
* Ursa can stack damage with Fury Swipes easily against her Mana Shield in a prolonged team match.
Additional:
* Medusa's tankiness doesn't help her very much against Fury Swipes in long teamfights.
* With no escape mechanism and a slow movement speed, getting jumped on by Ursa usually spells a quick end for Medusa in the early game.
Slark
* Medusa is especially vulnerable to Essence Shift, as both strength and intelligence contribute to her effective HP, while agility contributes to her damage.
* Dark Pact when timed right can be used to dispel Stone Gaze right after it petrifies Slark, allowing him to keep attacking Medusa throughout the duration.
Additional:
* Medusa cannot chase Slark in any way and has no disable beyond her ultimate, making her unable to stop him getting away and regenerating before coming back to finish her off.
* Essence Shift particularly removes 1 intelligence point per hit, thus lowering Medusa's mana pool's cap and leaving her much more vulnerable in prolonged fights.
Ursa
* Earthshock can slow down Chen and deal damage to both, Chen and his creeps.
* Many stacks from Fury Swipes combined with Overpower can guaranatee a kill for Ursa before Chen can save his allies with 
Hand of God.
* Enrage only makes Chen's attacks and his creeps's attacks tickle Ursa.
Slark
* Heroes that can easily bypass Chen's creeps to get to Chen: Riki, Tusk, Clinkz, Sniper, Slark, Phantom Assassin, Void Spirit, Storm Spirit, 
Ember Spirit, Earth Spirit, Spirit Breaker.
Ursa
* Early game gankers can make life very difficult for a Sniper if he keeps being caught: Ursa, 
Pudge, Earth Spirit.
Slark
* Sniper hugely lacks mobility and escape abilities so that he is an easy target for ganks from Slark.
Ursa
* Ursa can easily unleash a number of attacks in an incredibly short amount of time, easily destroying the 
Supernova in a couple of seconds regardless of Fire Spirits' debuff. His Enrage also dampens any damage Phoenix might toss at his direction, as well as remove any debuffs Phoenix may place on him.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Ursa
* Fury Swipes is not protected by 
Blade Fury and allows Ursa to harass Juggernaut anytime.
* Enrage reduces the damage taken from 
Omnislash.
Slark
* Heroes with escaping and disjointing abilities can be good against Juggernaut:Anti-Mage Riki, Queen of Pain, Puck, Storm Spirit, Ember Spirit, Slark etc.
Additional:
* Blade Fury does not offer any protections against Essence Shift, as it can go through spell immunity and reduces attribute.
* Slark can pounce away from Juggernaut and he cannot prevent or chase slark.
* Shadow Dance prevent Juggernaut from using Omnislash altogether, while regen himself at a higher rate. Slark can freely hit juggernaut without any fears of retaliation.
Ursa
* Ursa can shred Warlock's Golems in a few seconds with Fury Swipes and Overpower.
Slark
* 
Upheaval does not interrupt Slark too much, as he can just Pounce out of the area.
* 
Fatal Bonds and 
Shadow Word can be dispelled by Dark Pact.
Slark
* Rubick usually positions in the back of a team. Heroes who can sneak up and assault Rubick (e.g. Slark) or damage Rubick from great distance (e.g. Spectre, Sniper) should be treated cautiously, as otherwise the matchup usually ends up badly for Rubick.
Ursa
* 
Fade Bolt is not enough to burst Ursa, and even more so with Enrage active.
* The damage reduction from Fade Bolt is not effective due to Fury Swipes.
* Enrage lessens the lockdown duration from 
Telekinesis due to its status resistance.
* Ursa can easily melt 
Rubick down with Fury Swipes and Overpower if he gets close enough.
* Few of Ursa's spells grants utility for Rubick, as Rubick cannot steal the Fury Swipes passive.
* Enrage provides Rubick with some sort of survivability, yet Rubick generally wastes the duration in the front line as he does not have a constant damage source.
Slark
* Pounce and Dark Pact together with some attacks can take Rubick down quickly.
* Rubick's spells are ineffective due to the strong dispel effect of Dark Pact.
* Even though Shadow Dance is a great spell to steal, Slark's untargetable nature and his low cooldown spells prevents Rubick from stealing. Also Slark can freely use other abilities for the duration of Shadow Dance.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: Silencer, Death Prophet, Puck, Doom.
Ursa
* Silencer relies on preventing enemies from using abilities in teamfights with Arcane Curse, Last Word, and Global Silence. However, they are ineffective against Ursa since he relies more on items and attacks than abilities.
* Against a carry Silencer, Enrage can help Ursa reduce all damage he takes, even Glaives of Wisdom's pure damage will just tickle Ursa while his Enrage is active.
Slark
* Slark's Dark Pact allows him to dispel Silencer's debuffs.
* Against a carry Silencer, Essence Shift will lower damage from both Glaives of Wisdom and his basic attack.
Slark
* Heroes with heavy magical nukes will take advantage of Slark's poor HP or force him to use Shadow Dance early: Lina, Lion, Zeus
Ursa
* 
Light Strike Array has a long delay, making her vulnerable for Ursa's burst.
* Enrage can protect Ursa against Lina's high magical burst.
Slark
* Dark Pact can be cast during the cast animation of Light Strike Array and dispel its stun.
* Pounce allows Slark to close the gap to Lina.
* Shadow Dance prevents Lina from killing Slark with her Laguna Blade when his HP gets low.
Ursa
* With Aghanim's Scepter upgraded 
Infest, Lifestealer can use it on enemy heroes to attack them and disarm them from inside, even if they are spell immune, which can give him the edge over the heroes he's weak against like Ursa, Phantom Assassin, Terrorblade or Troll Warlord.
Ursa
* Lifestealer will struggle to duel Ursa in all stages of the game due to Fury Swipes, which pierces magic immunity. Ursa can also stand up to Lifestealer with Enrage, which dramatically reduces incoming damage and further delay Lifestealer's Feast.
Additional:
* Lifestealer's 
Feast will most likely not out-heal the damage from Fury Swipes and Overpower in the early to mid game.
Slark
* Shadow Dance allows Slark to attack Lifestealer for its duration without any way for Lifestealer to fight back, allowing him to steal his stats with Essence Shift, which also reduces Lifestealer's strength and, therefore, health pool.
* Slark can easily escape Lifestealer with Pounce, and can avoid Open Wounds with Dark Pact should Lifestealer be forced to itemize for it.
* Slark commonly buys a 
Silver Edge, which can break Lifestealer's Feast, severely diminishing his damage output and lifesteal.
* Depth Shroud from Aghanim's Shard allows Slark to save both, himself and his allies with Shadow Dance while also allowing them to fight back against Lifestealer.
Ursa
* Heroes with either magical, physical or pure damage burst: 
Bane, Ember Spirit, Leshrac, Lina, 
Luna, Nyx Assassin, Phantom Assassin, 
Skywrath Mage, 
Tinker, Ursa, Void Spirit.
Slark
* Heroes that can easily bypass Io's allies to get to Io: Riki, Tusk, Clinkz, Sniper, Slark, Phantom Assassin, Void Spirit, Storm Spirit, Ember Spirit, Earth Spirit, Spirit Breaker, Lifestealer.
Ursa
* Enigma lacks burst damage, and that makes him vulnerable to heroes who can recover themselves and turn the fight around to their advantage after Enigma finishes his initiation: Faceless Void, Terrorblade, Ursa, Weaver, 
Broodmother, Slark, Abaddon, Wraith King, Lifestealer.
Slark
* Enigma lacks burst damage, and that makes him vulnerable to heroes who can recover themselves and turn the fight around to their advantage after Enigma finishes his initiation: Faceless Void, Terrorblade, Ursa, Weaver, Broodmother, Slark, Abaddon, Wraith King, Lifestealer.
Ursa
* Ursa can deal lots of damage during the laning phase before Terrorblade can have 
Sunder available.
* Even if Terrorblade succeeds to use Sunder on Ursa, Enrage's damage reduction can help Ursa survive after Terrorblade has used Sunder him while also making Terrorblade's attacks tickle, even during Metamorphosis for it's duration.
Slark
* Dark Pact can dispel Venomous Gale and Poison Sting.
* Shadow Dance allows Slark heightened regeneration when out of vision making DoTs effects less threatening.
Slark
* Dark Pact easily purges away both slow and disarm effect from Lucky Shot.
* With Pounce now applying leash to the target, Pangolier is helpless against Slark since both his Swashbuckle and Rolling Thunder will be disabled. Pounce also help Slark to easily escape from Rolling Thunder.
Slark
* If Slark sees the Sacred Arrow before it hits him, he can use Dark Pact to remove it a moment later.
* Pounce prevents Mirana from escaping with Leap.
* Slark can survive Mirana's Aghanim's Scepter​ combo with Shadow Dance.
Slark
* Essence Shift allows Slark to hit Bristleback freely whether on the front or back, stealing attributes and make Bristleback much less tanky.
* Pounce can be used to disengage and recover lost HP with his ultimate passive, and can return to fight in a short period while Bristleback is already injured and got some of his attributes stolen.
* Dark Pact makes it near impossible to keep the 
Viscous Nasal Goo debuff on Slark.
* Although Dark Pact cannot dispel 
Quill Spray, meaning that Slark will still receive quill stack damage even if he used Shadow Dance before.
* Slark builds Silver Edge in almost every game, an item that greatly counters Bristleback.
Ursa
* Fury swipes can tear Dragon knight down as it stacks infinitely.
Slark
* Heroes with heavy magical nukes will take advantage of Slark's poor HP or force him to use Shadow Dance early: Lina, Lion, Zeus
Ursa
* Enrage will make it very difficult to burst him down.
* Zeus has little armor, HP and mobility; Ursa's favorite kind of target.
Slark
* Zeus can deal a huge amount of damage, but he lacks defensive abilities, such as good mobility or resistance. Due to that, he doesn't like to be touched by any means. Heroes with higher damage output and good mobility will often get easily near Zeus and trade damage (eventually causing Zeus's downfall). Such Heroes include: Lycan, Slark, Storm Spirit, Spectre and others.
Slark
* Essence Shift deals 20 extra damage by draining one strength per hit, which cannot be reduced or spread by 
Dispersion.
* Pounce prevents Spectre from escaping with 
Spectral Dagger.
* 
Haunt illusions usually don't deal a lot of damage to Slark as he tends to buy a Shadow Blade, preventing 
Desolate's and Diffusal Blade's damage and activating Shadow Dance's regeneration to make up for any damage caused by 
Radiance.
* Slark is a natural carrier of Silver Edge, which helps break both Desolate and Dispersion.
Ursa
* Jumping on Ursa with Life Break is often suicide for Huskar, as he will be immediately bursted down with Fury Swipes.
Additional:
* Huskar likes fights with a long duration and is usually at low health, making him vulnerable against Ursa's physical damage.
* Jumping in with Life Break against Ursa is suicide, as Enrage, Overpower, and Fury Swipes will easily shred Huskar.
Ursa
* Ursa can do damage very fast with his Overpower and Fury Swipes abilities, Necrohops will have taken large amounts of damage before he can use Ghost Shroud, And if Ursa has Skull Basher, Ursa will quickly demolish Necrophos before he can do anything to retaliate.
* Skilled and smart Ursa can bait Necrophos into using Reaper's Scythe on him, and with his Aghanim's Scepter upgraded Enrage that can negate 80% of the damage, Ursa will often survive and waste Reaper's Scythe.
Slark
* With Dust of Appearance, Luna will be able to use 
Eclipse on invisible heroes. Be mindful that Slark is exception because he'll be able to remove the debuff with Dark Pact.
Ursa
* All assassin-type carries in a one against one situation: Meepo, Phantom Assassin, Riki, Ursa. Luna's only chances are that she buys 
Ethereal Blade or Black King Bar to gain a slight edge against them, or both items if necessary.
Slark
* Shadow Dance prevents Luna from damaging Slark, and together with Silver Edge he can easily chase her or escape from her.
* Luna has no way to escape from Pounce's leash.
* For the same reasons, Slark makes a very powerful ally for Luna when they are in the same team.
Additional:
* Luna's lack of mobility and escape abilities makes her easily to gank for Slark.
* Shadow Dance helps avoid all the damage from Eclipse.
* For the same reasons, Slark makes a very powerful ally for Luna when they are in the same team.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Additional:
* Timbersaw can use 
Chakram as a scouting tool to find Slark if he tries to Pounce into the trees.
* None of Timbersaw's abilities require a target to be cast, allowing him to hit Slark inside Shadow Dance.
* 
Reactive Armor can be effective protection against a Slark who attacks quickly, since the strong armor and health regen cannot be stolen by Essence Shift.
* 
Timber Chain makes Timbersaw very mobile, meaning he is among the very few heroes who can actually give chase to a fleeing Slark.
Ursa
* Timbersaw's physical survivability revolves around Reactive Armor, which is largely ignored by Fury Swipes due to the extreme amounts of damage it does in a very few number of attacks.
* Timbersaw's burst damage will not do much against Enrage, although he could easily use Timber Chain to escape, wasting the duration of it.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* A well-timed Dark Pact can dispel Frost Arrows and Gust, letting Slark engage and escape freely.
* Essence Shift is very detrimental for Drow Ranger as the loss of agility means that Marksmanship will also suffer from getting weakened.
* Shadow Dance lets Slark quickly close the gap and deal heavy damage without giving Drow Ranger a chance to retaliate.
* Pounce counteracts Frost Arrows's slow, and also allows Slark easily pin Drow Ranger down or flee from her.
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies and will also allow them to freely fight back against Drow Ranger without her noticing them.
Additional:
* Pounce and items like Shadow Blade makes it very difficult for Drow Ranger to keep her distance from Slark, thereby losing her 
Marksmanship bonus.
* 
Gust is rarely enough to keep Slark at bay, as Drow Ranger has no movement abilities and will simply be chased down afterwards.
* Drow Ranger's heavy dependence on agility also makes her significantly weaker after being drained by Essence Shift.
Slark
* Dark Pact dispels Ignite's slow and Fireblast's stun.
* Shadow Dance allows Slark to regenerate HP, even when he is affected by Ignite and Fireblast.
Ursa
* Ursa's massive physical damage can destroy Kunkka quickly.
* Enrage can be activated before being hit by Ghostship to prevent most of the damage.
* Earthshock slows Kunkka's movement speed. With no escape abilities, Kunkka is easy prey.
Ursa
* Heroes who can provide constant vision inside the Roshan Pit can negate one of the strongest advantages of Ursa, which is the possibility of quickly killing Roshan at the early game, with minimum itemization needed (
Clockwerk, 
Beastmaster, etc).
Ursa
* Ursa's high physical burst damage combined with his big attack speed and durability makes him a very bad target for Power Cogs.
* Even with 
Blade Mail, Ursa's Enrage will negate most of the reflected damage.
Slark
* Clockwerk lacks burst damage, and that makes him vulnerable to heroes who can recover themselves and turn the fight around to their advantage after Clockwerk finishes his initiation. Additionally, Clockwerk hates buying 
Dagon and Ethereal Blade, which are the only itmes that can help him deal with heroes who can recover themselves and turn the fight around to their advantage: Faceless Void, Terrorblade, Ursa, Weaver, Broodmother, Slark, Abaddon, Wraith King, Lifestealer.
Ursa
* Fury Swipes can give Ursa the edge in Duels.
* Enrage's instant cast time allows it to be used before Legion Commander initiates a Duel, causing Ursa to take almost no damage for a brief period of time.
* However, Duel stops Ursa from casting Enrage at the most critical moment
Slark
* Dark Pact, if timed correctly, can dispel Wraithfire Blast's stun and slow.
* Since Wraith King has a lot of health and multiple lives, Slark can keep gaining Essence Shift stacks, increasing armor, damage, and attack speed and can beat down Wraith King twice.
* Slark sometimes carries Diffusal Blade to burn mana as an attempt to shut down Reincarnation.
* Because Wraith King has no AoE abilities, Shadow Dance is particularly useful against Wraith King.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Pounce also stops Nature's Prophet's 
Teleportation.
Slark
* Heroes who build Black King Bar as either core or situational item will be able to fight back against Nyx Assassin and freely attack him as Spiked Carapace cannot pierce spell immunity at all: Axe, Broodmother, 
Dawnbreaker, Enigma, 
Huskar, Jakiro, 
Legion Commander, Lina, Luna, Lycan, Slardar, Slark, Troll Warlord, Witch Doctor.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Ursa
* Heroes with burst damage of their own won't be afraid to go toe to toe with Void Spirit, like Ursa, Lifestealer, or Axe.
Ursa
* Low mobility heroes: Heroes with no/little means of traveling fast have difficulty getting to/away from Bounty Hunter due to his slowing Jinada and hastening Track. Few examples of such heroes are: Crystal Maiden, Sniper, Ursa, Witch Doctor, etc.
Ursa
* Ursa with Enrage
* Heroes that can remove the Track debuff with their skills:
* Abaddon with 
Aphotic Shield and 
Borrowed Time
* Huskar with 
Life Break
* Juggernaut with Blade Fury
* Legion Commander with 
Press the Attack
* Lifestealer with 
Rage and Infest
* 
Naga Siren with 
Mirror Image
* 
Omniknight with 
Heavenly Grace
* Oracle with 
Fortune's End and 
False Promise
* Phantom Lancer with Doppelganger
* Slark with Dark Pact
* Ursa with Enrage
* Weaver with Time Lapse
* 
Tidehunter with 
Kraken Shell when damage received reaches the threshold.
Slark
* Slark with Dark Pact
* Heroes that can remove the Track debuff with their skills:
* Abaddon with Aphotic Shield and Borrowed Time
* Huskar with Life Break
* Juggernaut with Blade Fury
* Legion Commander with Press the Attack
* Lifestealer with Rage and Infest
* Naga Siren with Mirror Image
* Omniknight with Heavenly Grace
* Oracle with Fortune's End and False Promise
* Phantom Lancer with Doppelganger
* Slark with Dark Pact
* Ursa with Enrage
* Weaver with Time Lapse
* Tidehunter with Kraken Shell when damage received reaches the threshold.
Slark
* Nyx Assassin, Bounty Hunter and Slark can all sneak up and kill Shadow Shaman, Nyx being particularly deadly. Shadow Shaman must watch out for Slark carefully, as he can break either (but not both unless he makes a mistake) of Shadow Shaman's disables, with Dark Pact and leap out of a serpent ward ring. These heroes, however, rely heavily on escape and are themselves not very durable and none of them can survive a full lockdown with Mass Serpent Ward. Having Sentry Wards can turn Shadow Shaman from prey to predator.
Slark
* Heroes who have a high mobility (Queen of Pain, Storm Spirit, Slark, etc.).
Slark
* Melee carries who usually buy an early Black King Bar, and have gap closing abilities can be good against the Arc Warden, such as Slark, Riki, Earthshaker with Aghanim's Scepter, Sven with Aghanim's Scepter etc.
Additional:
* 
Flux is dispelled by Dark Pact.
* Pounce allows Slark to avoid 
Spark Wraiths.
* 
Tempest Double allows Slark to build up Essence Shift stacks, especially when it is being used for split pushing.
Ursa
* Heroes who can delivers a big chunk of damage in few hits will find themselves struggle against Templar Assassin's Refraction: Sven, Phantom Assassin, Ursa, Wraith King, Lifestealer
Additional:
* Templar Assassin usually places 
Psionic Traps inside the Roshan Pit (and can teleport herself to the traps with an Aghanim's Scepter), preventing Ursa from killing Roshan without getting noticed by the enemy team.
Slark
* Dark Pact rips through 
Refraction charges and still steals attributes during Refraction.
* Pounce and Dark Pact will still hit Templar Assassin while she is 
Melded. Since she cannot move, both abilities will be easy for Slark to land.
Ursa
* Heroes with evasions: Phantom Assassin, 
Brewmaster, 
Hoodwink, 
Windranger.
Slark
* Slark's Pounce can be used to dodge Hoodwink's abilities or lock her down.
* Shadow Dance makes Slark unhittable from 
Acorn Shot.
* Dark Pact removes all slows from Hoodwink's abilities.
* Hoodwink's already low health output is a great target for Slark's Essence Shift.
Slark
* Heroes who build mana boosting items but have low mana regeneration are especially vulnerable against Mana Break and Mana Void: Timbersaw, Slark, Shadow Fiend, Clinkz, Bristleback Nyx Assassin, Magnus
Slark
* Pounce prevents Anti-Mage from using Blink, and lets him disengage from Anti-Mage if needed.
* Essence Shift allows Slark to permanently steal agility from Anti-Mage.
* Shadow Dance stops Anti-Mage from being able to fight back in a slippery situation.
Ursa
* Assuming they have not bought anti-evasion items, attack-dependent heroes such as Ursa, Terrorblade or Lifestealer can be a minor threat for Phantom Assassin early in the game, and may even be completely dominated by her thanks to her evasion.
Slark
* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with 
Phantom Strike.
* As a hero who typically builds Silver Edge, Slark can use it to disable Phantom Assassin's 
Blur and 
Coup de Grace, thus taking down her attack evasion and drastically reducing her damage output.
* Because Phantom Assassin is always reliant on critical strikes, Slark will have plenty of time to escape with Pounce, Shadow Dance and Silver Edge (provided that he purchased it already).
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies from Phantom Assassin with Shadow Dance, and to freely fightback against her without removing invisibility upon attacking.
* Essence Shift is much more harmful for Phantom Assassin than for other heroes, as losing the agility means that her physical damage will be also reduced, which can also weaken Coup de Grace if Slark manages to steal lots of agility from her.
* Overall, any attempt for Phantom Assassin to take down Slark will hurt her more than Slark.
Additional:
* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with Phantom Strike.
* As a hero who typically builds Silver Edge, Slark can use it to disable Phantom Assassin's Blur and Coup de Grace, thus taking down her attack evasion and drastically reducing her damage output.
* Because Phantom Assassin is always reliant on critical strikes, Slark will have plenty of time to escape with Pounce, Shadow Dance and Silver Edge (provided that he purchased it already).
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies from Phantom Assassin with Shadow Dance, and to freely fightback against her without removing invisibility upon attacking.
* Essence Shift is much more harmful for Phantom Assassin than for other heroes, as losing the agility means that her physical damage will be also reduced, which can also weaken Coup de Grace if Slark manages to steal lots of agility from her.
* Overall, any attempt for Phantom Assassin to take down Slark will hurt her more than Slark.
Ursa
* Positioning-reliant heroes (Windranger, Tidehunter, Ursa...), since Earth Spirit can disrupt positioning with his Boulder Smash.
Slark
* Pounce's root prevents Earth Spirit from using Rolling Boulder to escape, making it easier for Slark to shut him down especially in the laning phase.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Ursa
* Fury Swipes damage is not reduced by 
Atrophy Aura, essentially bypassing Underlord's only natural defense.
* Enrage can easily dispel the root of 
Pit of Malice.
* However, Ursa has nothing to intercept Underlord and his team when they are grouped up for the teleportation with 
Fiend's Gate outside of Earthshock.
Slark
* Melee carries during the laning phase: Sven, Slark
Slark
* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer
Slark
* Shadow Dance does not protect Slark from Shadow Fiend's AoE spells.
Ursa
* Earthshock prevents Shadow Fiend from escaping after Ursa used his Blink Dagger to get on top of him.
* Overpower and Fury Swipes allow Ursa to quickly kill Shadow Fiend.
* Enrage keeps Ursa alive in a manfight with Shadow Fiend and allows him to stay close, even if Shadow Fiend uses Requiem of Souls.
Slark
* 
Nether Blast will still hit Slark even if he is hidden during Shadow Dance.
* Even though Pugna can rarely target Slark directly with 
Decrepify, he can still use it defensively on an ally to prevent Slark from getting stacks.
* Despite being somewhat easy to break with Pounce, Pugna can damage Slark and provide vision over him with 
Life Drain.
Ursa
* If Ursa uses Enrage, Pugna's Life Drain is next to worthless against him, due to Ursa taking 80% less damage, therefor Pugna heals by only 20% of the damage that the spell normally deals.
* It also dispels Decrepify, Even if you wait until he casted it, he can still dispel it with Shard upgraded Earthshock
* Ursa also commonly builds Skull Basher. With his high Attack Speed from Overpower. he can easily cancel Life Drain
* If Decrepify is defensivly casted, Ursa can still cast Earthshock both to slow you, and to deal amplified magic damage. He also commonly builds a 
Nullifier
* If Ursa jumps on you with a Blink Dagger he can easily wipe you out with Overpower.
* Ursa's Overpower can destroy a full health 
Nether Ward and still have a few swipes leftover, Also Ursa's low mana spells means he takes negligible damage from the Nether ward anyway.
* Ursa is also a common Diffusal Blade carrier, using it to both amplify his damage, but as his primary way to catch fleeing heroes
* Pugna is also the primary target of Ursa, due to him being both quite squishy, and a serious threat to his team, Ursa prioritizes the weakest link as Fury Swipes stacking damage will quickly demolish them, allowing Ursa to safely switch heroes
Ursa
* Plasma Field can spot an Ursa sneaking into Roshan's pit
* Static Link has a 800 link break distance, meaning Razor can stay close enough to drain Ursa' damage, but not too close to get attacked
* Static Link cannot be dispelled by Enrage
* With Storm Surge, Razor will usually be faster than Ursa in most cases
* Eye of the Storm melts through Ursa's armor
Slark
* Pounce can easily break Static Link, making it less powerful against him.
* Slark is one of the few heroes who can man fight a Razor, because of Essence Shift.
* Shadow Dance can prevent Razor from killing him and may provide an opportunity to kill Razor due to it preventing Razor from attacking Slark.
Ursa
* Ursa relies on the Blink-Earthshock combo to slow enemies to burst them, but Windranger can use 
Windrun to escape through Earthshock's duration.
* Windrun and 
Focus Fire can easily allow Windranger to kite Ursa and do good amounts of damage in the process.
Additional:
* Windranger can avoid Ursa's primary source of damage, Fury Swipes, by simply using Windrun. The slow from Earthshock is also rendered irrelevant by Windrun.
* Focus Fire and Windrun can be used to kite Ursa.
Slark
* Pounce helps put Windranger in place, even when she uses Windrun to escape.
* Shadow Dance avoids Windranger's attacks from Focus Fire altogether, and he can regenerate his health and fight back after Windranger uses up all her abilities.
* The stun from 
Shackleshot and the slow from
Powershot can be both dispelled by Dark Pact, provided Slark casts it at the right moment.
Slark
* Earthshaker's many stuns can lock down slippery heroes like Slark in his Shadow Dance and Weaver in his Shukuchi.
Additional:
* Earthshaker's many AoE stuns help lock down Slark and will often waste the duration of Shadow Dance.
* As a frequent 
Force Staff buyer, he can later on escape or save teammates from Pounce.
Slark
* Heroes with invisibility and high mobility can jump on and focus down Earthshaker before he has a chance to initiate: Clinkz, Slark, Storm Spirit
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Slark
* Dark Seer relies on Surge for most of his mobility, so he's not very vulnerable to slows, but much more to root effects and walls or pseudo-walls such as Disruptor's Kinetic Field or Slark's Pounce.
Slark
* Berseker's Call catches Slark in Shadow Dance, wasting its duration and preventing him from escaping to regenerate.
* Unlike most disables, Dark Pact cannot dispel Berserker's Call and the output damage would be returned by Blade Mail.
Additional:
* 
Berserker's Call forces Slark to attack him, even during Shadow Dance.
* 
Counter Helix will hit Slark in Shadow Dance. It will also trigger frequently against Slark's high attack speed provided by Essence Shift stacks.
* 
Culling Blade finishes off Slark before he gets a chance to slip away and regenerate his health, preventing him from playing his typical hit-and-run style.
Ursa
* Enrage reduces the damage from Blade Mail and Counter Helix to a minimum, forcing Axe to play around Ursa's ultimate ability.
* Overpower and Fury Swipes stacks damage overwhelming for Axe, despite his high health.
Ursa
* Laser can be cast on a initiating Ursa, normally causing him to waste multiple Overpower attacks, forcing him to either Black King's Bar, or Enrage to protect himself.
* Ursa will probably carry a Linken's Sphere to counter Tinker's Laser. Popping it with Scythe of Vyse is actually preferable, due to Laser's high Pure damage.
* While Ursa is a common Blink Dagger carrier, but he otherwise has no way to close the gap, Baiting him into using his Blink, then blinking away, allows Tinker to easily kite Ursa.
* Enrage is generally how Ursa disengages, Due to Tinker's high maneuverability, he can follow him until it runs out. then burst him down with high magic damage.
Slark
* Pounce prevents Tinker from blinking away.
* Slark frequently builds Shadow Blade, which allows him to approach Tinker unnoticed. Since Tinker's farming usually covers a significant amount of area on the map, Sentry Wards may not be cost effective.
* Shadow Dance allows Slark to detect both common and unusual wards. Eliminating common ward causes Tinker trouble farming many lanes if he does not know who may be waiting to jump on him. Slark is also uniquely able to identify some of the less common wards used by Tinker, such as those placed on the cliffs at map edges which Tinker uses to give him vision over the trees he uses to hide in.
* Slark's extremely high move speed from Shadow Dance, potentially stacked with Shadow Blade, allows him to easily follow Tinker between lanes, especially if Tinker has pushed the lanes out.
* Dark Pact dispels Laser's blind.
Ursa
* Ursa cannot effectively fight against Phantasm's illusions with his single-target damage.
Enrage.
Chaos bolt and 
Phantasm combo. 
Reality Rift can quickly relocate or reinitiate on Ursa once the duration of 
Enrage is over. 
Phantasm can be used to dispel Earthshock's slow. 
Manta Style is another item that counter Ursa greatly. 
Reality Rift, Ursa struggles to escape.
* Chaos Bolt's potentially long stun with Chaos Bolt gives Ursa little opportunity to
Additional:
* Ursa has no way to clear illusions quickly, making him vulnerable to
*
*
* Ursa has low mobility, once jumped on by
Slark
*
Dark Pact is minimally effective against Phantasm illusions, and Slark lacks area damage otherwise.
Pounce can be counteracted by Reality Rift.
Essence Shift stacks.
Shadow Dance can make Slark hard to kill as he can't be targeted during its duration.
Phantasms have enough health to survive Dark Pact, and Slark has no other source of AoE damage to deal with them.
*
* Slark is naturally frail and dies quickly to Chaos Knight's burst damage before he can build
* Be aware, however, that
Additional:
*