Lycan
* 
Guardian Angel completely negates all of Lycan's damage since Lycan mainly deals physical damage.
* 
Purification can also be a problem for Lycan, as Purification deals damage around the target, which poses a problem for him and his summons.
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.
Lycan
* Melee heroes who rely on summons, illusions, or clones will trigger Counter Helix more often, thus taking more damage: 
Meepo, 
Lycan, 
Phantom Lancer
Additional:
* 
Berserker's Call can keep Lycan in place during his Shapeshift even through 
Black King Bar.
* 
Counter Helix is very effective against Lycan because of his summons.
* 
Culling Blade will prevent Lycan from running away with Shapeshift when he drops low.
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.
Lycan
* 
Pugna's 
Decrepify prevents the target from taking physical damage or doing damage, which poses a huge problem for Lycan, as he mainly deals physical damage.
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.
Lycan
* Heroes who rely heavily on melee attacks and lack early spell immunity are easily blocked and interrupted by Ink Swell: Lycan, 
Ursa, 
Troll Warlord.
Additional:
* 
Stroke of Fate deals more damage when it hits more targets which makes it very effective in dealing with Lycan and his units.
* 
Soulbind prevents Lycan from running away and makes him very easy to deal with.
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.
Lycan
* 
Great Cleave will kill Lycan's summons very rapidly.
* 
Warcry will allow Sven and his allies to tank Lycan's damage, which is mainly physical.
* 
Storm Hammer will damage and stun Lycan's as well as his summons.
Slark
* Heroes who cannot prevent Sven from killing supports will always be at a disadvantage in fights such as 
Lina, 
Slark and 
Zeus.
Lycan
* Lycan is a hero focused entirely on single target physical damage and lacks disables or AoE damage. Due to this, he will have difficulties dealing with illusions or Naga Siren's Ensnare.
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.
Lycan
* Heroes who summon multiple units that are not spell immune. 
Nature's Prophet,Lycan,
Beastmaster
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, 
Jakiro, 
Underlord, 
Leshrac, 
Dark Seer, 
Earthshaker, 
Timbersaw, 
Crystal Maiden.
Lycan
* Jakiro's area-of-effect abilities make him strong against heroes who rely on illusions and summons: 
Terrorblade, 
Naga Siren 
Chaos Knight, Phantom Lancer, 
Broodmother, Nature's Prophet, Lycan, 
Wraith King, 
Visage.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
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.
Lycan
* Brewmaster can waste a large portion of Lycan's ultimate by putting him in Cyclone.
* Lycan has no way to stop Brewmaster from using Primal Split by himself.
* Lycan's team often tries to push towers as a group, and Brewmaster excels at winning teamfights while trying to defend a tower.
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.
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.
Lycan
* A well landed 
Fissure can potentially take Lycan out of the fight for several seconds, who heavily relies on precious seconds from Black king bar and Shapeshift to fight.
* 
Aftershock reduces the effectiveness of his summons and can prove quite irritating for Lycan.
* 
Echo Slam is very powerful with the sheer amount of Lycan's units and will cause him to think twice when pushing towers.
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
Lycan
* Paralyzing cask bounces between him and his wolves, keeping him stunned for long amounts of time.
Slark
* Dark Pact is minimally effective against Phantasm illusions, and Slark lacks area damage otherwise.
* 
Pounce can be counteracted by Reality Rift.
* Slark is naturally frail and dies quickly to Chaos Knight's burst damage before he can build Essence Shift stacks.
* Be aware, however, that Shadow Dance can make Slark hard to kill as he can't be targeted during its duration.
Additional:
* 
Phantasms have enough health to survive Dark Pact, and Slark has no other source of AoE damage to deal with them.
Lycan
* Tidebringer's cleave will cripple any of his summons.
* Could potentially build Heaven's Halberd to cripple Lycan even more.
Additional:
* 
Tidebringer can be used to kill Lycan's summons.
* Can also build into 
Heaven's Halberd which will disable Lycan's auto attacks, crippling him even more.
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.
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.
Lycan
* All of Timbersaw's spells deal AoE damage, killing Lycan's summons very quickly.
* 
Reactive Armor will gain stacks quickly because of Lycan's summons.
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.
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.
Lycan
* Heroes who rely on physical damage output to be effective will fare badly against Muerta's 
Pierce the Veil: Phantom Assassin, Terrorblade, 
Drow Ranger, 
Lifestealer, Anti-Mage, 
Alchemist, Lycan, Clinkz, 
Sniper.
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.
Lycan
* Heroes with abilities that can close the gap can easily kill Muerta: Storm Spirit, Earth Spirit, 
Ember Spirit, 
Void Spirit, Lycan, Chaos Knight, Tusk.
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.
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
* Shadow Dance does not protect Slark from Shadow Fiend's AoE spells.
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.
Lycan
* Faceless Void can lock Lycan down with his 
Chronosphere pinning him down as long as his ultimate is up.
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.
Slark
* Heroes that can deny Slark early kills will prevent him from snowballing: 
Dazzle, 
Abaddon.
Lycan
* Heroes with summoned units don't fare well against Dawnbreaker. (Phantom Lancer ,Beastmaster ,Lycan).
Lycan
* Heroes who rely on summons will see them destroyed easily by Overwhelming Odds: Lycan, 
Arc Warden, 
Warlock, 
Chen
Lycan
* Heroes that can summon units will have their summons destroyed very quickly if badly micro-managed, like Chen, Lycan, and Phantom Lancer.
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.
Lycan
* Heroes that heavily depend on illusions or summons, (Naga Siren, Terrorblade, Phantom Lancer, Lycan,...) are vulnerable to Sleight of Fist and even more so if Ember Spirit has 
Battle Fury.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: 
Silencer, 
Death Prophet, Puck, 
Doom.
Slark
* 
Slardar's level 25 talent makes 
Corrosive Haze undispellable, thus providing his allies vision of Slark.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Slark
* Heroes that can deny Slark early kills will prevent him from snowballing: Dazzle, Abaddon.
Lycan
* 
Dragon Knight's insanely high armor and splash damage can cause Lycan to struggle taking him down.
Lycan
* 
Treant Protector grants protection against his attacks with 
Living Armor and his ultimate, 
Overgrowth is a massive AoE disarm and root that pierces spell immunity, causing trouble to Lycan. You will find yourself in need of an ally's dispel or forced to pop Black King Bar for its dispel.
Additional:
* Lycan has no kind of teleport, being only able to walk, and heavily relies on his attacks. As Overgrowth roots and disarms the targets, Lycan can't do much in an overgrowth field.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: Silencer, Death Prophet, Puck, Doom.
Lycan
* Can cast 
Demonic Conversion on one of Lycan's Wolves, making this a numbers fight.
* 
Malefice will greatly reduce his ability to engage
* 
Midnight Pulse can steep an area making it harder for Lycan to engage in.
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.
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.
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.
Lycan
* 
Primal Roar allows Beastmaster to keep Lycan in place after he used his Shapeshift.
Slark
* Heroes with strong dispels can remove Primal Roar's stun: Abaddon, Slark, 
Oracle.
Lycan
* Heroes with summons and illusions can find themselves easily bested by Lina, like Broodmother, Nature's Prophet, Chen, Terrorblade, Naga Siren, Visage, Wraith King, Lycan, Phantom Lancer, 
Shadow Shaman.
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
* 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.
Lycan
* Mirana's Leap is ineffective if Lycan uses 
Shapeshift. It also allows him to dodge Sacred Arrow.
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.
Lycan
* Shapeshift allows Lycan to escape from Upheaval with maximum movement speed.
* Warlock doesn't have a good solution to deal with Lycan's wolves from 
Summon Wolves.
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.
Lycan
* 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
* Slark can detect early Roshan attempts due to Shadow Dance if he frequently checks the Pit.
* Enrage cannot restore attributes stolen by Essence Shift and will reduce his physical damage output.
* Even if Ursa initiates with Earthshock, Slark can Pounce away or use Dark Pact after Ursa's initiation to avoid Fury Swipes' damage until Earthshock's slow is gone.
Lycan
* Shapeshift allows Lycan to chase down Earth Spirit.
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.
Lycan
* Shapeshift allows Lycan to get close and disable Marksmanship.
* Shapeshift also makes him immune to slows like Drow Ranger's Frost Arrows.
Additional:
* The Wolves's speed causes the knockback from 
Gust to be ineffective.
* Drow Ranger lacks escapes and loses her 
Marksmanship when someone is near her. Lycan can take advantage of these weaknesses of Drow Ranger.
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.
Lycan
* The movement speed granted from Shapeshift means that Spectre has no way to punish Lycan if he wants to splitpush or pick off supports. Furthermore, he will kite 
Haunt and cannot be slowed by 
Spectral Dagger.
* Lycan is often part of an early game push strategy which is often the best counter to Spectre because she needs a lot of time and space to come online as a late game carry.
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.
Lycan
* Windranger tends to fare badly against high mobility heroes that can easily dodge Powershot, close the gap on her when she uses Windrun or escape from Focus Fire's reach. Examples of such heroes include Spirit Breaker, Lycan, Storm Spirit, Earth Spirit, Void Spirit, Slark and others.
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.
Lycan
* Multiple attackers thanks to summoned units or clones: Meepo, 
Witch Doctor, Lycan, 
Enigma, Shadow Shaman
* Heroes that can quickly deal damage to her, regardless of how weak they are, can easily break through her Refraction:
* Multiple attackers thanks to summoned units or clones: Meepo, Witch Doctor, Lycan, Enigma, Shadow Shaman
* Multiple attackers thanks to illusions: Phantom Lancer, Chaos Knight, Naga Siren (bonus for her Ensnare). Also despite the visual effects, Templar Assassin does not spill damage against illusions or buildings, so she is not a really good hero to clean up illusions.
* Weak damage but high tick rate or persist in a long time: Slark, 
Gyrocopter, Queen of Pain, Shadow Shaman (
Shackles), Jakiro, Pugna, Doom
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.
Lycan
* You can easily kill a squishy Sniper, due to your high movement speed and his lack of escape.
Slark
* Sniper hugely lacks mobility and escape abilities so that he is an easy target for ganks from Slark.
Lycan
* Lycan can clear waves of Chen's creeps with his wolves from Summon Wolves, especially once Lycan takes +2 Wolves summoned talent. And even though Chen can convert one of his wolves with 
Holy Persuasion, Lycan can counter this by buying 
Helm of the Overlord to regain control of it. Uncontrollable wolves summoned from Aghanim's Shard upgrade Summon Wolves cannot be converted with Holy Persuasion.
* Shapeshift allows him to chase down Chen and kill him easily.
* 
Howl can reduce attack damage of both, Chen and his creeps.
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.
Lycan
* Heroes with single-target abilities will be overwhelmed by Lycan and his summons: Wraith King, 
Bane, Phantom Assassin.
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.
Lycan
* Lycan's high health allows him to easily shrug off Nyx Assassin's burst damage and fend him off.
* As Lycan commonly buys Black King Bar, he can use it to freely attack Nyx Assassin and chase after him with Shapeshift.
* Lycan can also use his wolves from Summon Wolves to attack Nyx Assassin while he has 
Spiked Carapace active without getting stunned himself.
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.
Lycan
* 
Magnetic Field is useless against melee heroes, so Lycan can attack Arc Warden without missing.
* 
Flux doesn't affect Lycan that much, because Shapeshift grants immunity to slows and because he is never alone.
* If their 
Tempest Double has been called, Lycan can still kill Arc Warden before the double expires.
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.
Lycan
* Heroes with summons: Lycan, Broodmother, Visage, Nature's Prophet, Warlock.
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.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: Silencer, Death Prophet, Puck, Doom.
Lycan
* Shapeshift is useful for killing or escaping Silencer.
* Summon Wolves, can be used to hunt and harass silencer - even when Lycan himself can't fight.
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.
Lycan
* Heroes with both illusions and summons, for Io has nothing to deal with multiple enemies at once outside from Spirits's weak area-of-effect: Beastmaster, Broodmother, Chaos Knight, Lycan, Naga Siren, Nature's Prophet, Phantom Lancer, Shadow Shaman, Terrorblade, Visage, Warlock, Wraith King.
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.
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).
Lycan
* He can send wolves to defuse 
Proximity Mines, and he can catch up Techies and kill him before they can deny themselves. Even if the suicide is successful, Lycan can still survive because of his tankiness.
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
* 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).
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
* 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.
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.
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.
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.
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.
Lycan
* Heroes with single-target abilities will be overwhelmed by Lycan and his summons: Wraith King, Bane, Phantom Assassin.
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.
Lycan
* Howl reduces a good chunk of Marci's attack damage that she relies heavily on, and the armor reduction works better on her because of her low armor.
* Shapeshift renders Lycan immune to slow from Rebound and Unleash.
Lycan
* Lycan doesn't care much about Lich's slows thanks to Shapeshift.
* Chain Frost can bounce to the wolves that Lycan summons.
Additional:
* 
Lich possesses a lot of slows, which Lycan doesn't care about when he Shapeshifts.
* Lich has no in-built escape, which makes him a good target for Lycan.
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 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.
Lycan
* Heroes who can summon illusions and summons because Terrorblade has no abilities to deal with multiple enemies at once outside Reflection: Shadow Shaman, Naga Siren, Broodmother, Lycan, Enigma, Chaos Knight, Phantom Lancer, 
Shadow Demon, Dark Seer, Nature's Prophet, 
Invoker, Morphling, Visage, 
Grimstroke with Aghanim's Scepter.
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.
Lycan
* Once you get a Black King Bar, squishy spellcasters like Zeus, 
Skywrath Mage and others will be probably easy to deal with.
Lycan
* Phantom Assassin's 
Blur is a real problem for Lycan, as he relies entirely on direct attacks to deal damage.
Lycan
* Heroes with single-target abilities will be overwhelmed by Lycan and his summons: Wraith King, Bane, Phantom Assassin.
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.
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.
Lycan
* Heroes with low armor and little mobility, like Huskar, 
Io, etc. will also have an unfortunate fate.
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 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.
Slark
* Heroes who have a high mobility (Queen of Pain, Storm Spirit, Slark, etc.).
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
Lycan
* Once you get a Black King Bar, squishy spellcasters like Zeus, Skywrath Mage and others will be probably easy to deal with.
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
* 
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
* 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.
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
* 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.
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, which is especially bad as she is not used to buying 
Wind Waker, which is the only way to escape from Pounce outside of Black King Bar.
* 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
* 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.
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.
Lycan
* Heroes who have summons, which can be quickly cleared by his powerful area of effect skill: Nature's Prophet, Enigma, Lycan
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
* 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.
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 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.
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.
Lycan
* Shapeshift increases Lycan's movement speed and renders him unslowable, allowing him to easily avoid and escape Ancient Apparition's abilities.
* Lycan has fast summons, both his wolves from Summon Wolves can do heavy damage to Ancient Apparition due to his immobility and low armor.
Lycan
* Lycan relies heavily on right clicks making Untouchable very effective against him.
* If he tries to run away Impetus will do huge amounts of damage.
Additional:
* She can 
Enchant one of the wolves to her side.
* Lycan will struggle greatly to harm Enchantress through her 
Untouchable which can seriously slow down Lycan's attack speed even if Lycan is spell immune.
Lycan
* Heroes with haste can negate Enchant's slow: Weaver, Dark Seer, Lycan, 
Centaur Warrunner.
Slark
* Heroes that can jump on her: Slark, Queen of Pain, Anti-Mage
Lycan
* 
Charge of Darkness allows Spirit Breaker to catch up to Lycan after he uses Shapeshift.
Additional:
* Vision from Charge of Darkness will easier to catch Lycan Shapeshift and Charge of Darkness out of reach Lycan Summon Wolves and Lycan's other creeps. Until upgrade Aghanim's Scepter faster catching Lycan Shapeshift.
Lycan
* Heroes with summons and illusions as Spirit Breaker has no strong AoE capabilities to deal with them: Chaos Knight, Phantom Lancer, Terrorblade, Naga Siren, Broodmother, Warlock, Visage, Nature's Prophet, Shadow Shaman, Lycan, 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 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.
Lycan
* Lycan's wolves deal little damage to Bristleback, and are easily killed by Quill Spray, even when they're invisible.
* Lycan's lack of burst damage makes it very hard for him to kill Bristleback, especially when his back is turned.
Additional:
* 
Quill Spray can be used to kill Lycan's summons.
* 
Bristleback allows him to stay alive against Lycan while dishing out counter attacks
* He can overpower Lycan with his 
Warpath instead.
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.
Lycan
* Any Hero with high mobility will be neutralized by dream coil: Queen of Pain, Storm Spirit, Ember Spirit, Lycan, 
Bloodseeker, Anti-Mage, Timbersaw.
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.
Lycan
* A Lycan with Shapeshift can always run down Puck for a very quick kill due to its low armor. It is important to abuse as many cliffs and trees as possible to escape from a Lycan.
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.
Lycan
* 
Keeper of the Light has a blind, which causes Lycan to miss his attacks.
Slark
* Melee carries during the laning phase: Sven, Slark
Lycan
* Heroes with hastes: Dark Seer, Lycan
Slark
* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer
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.
Lycan
* Lycan and Weaver has abilities that allow them to move at maximum movement speed, and those abilities can't be dispelled, potentially wasting the slow from Demonic Purge.
Lycan
* Her 
Mana Shield is too tough for Lycan to break.
* 
Mystic Snake can hit for a massive damage once it spread between his summons.
Additional:
* Can be easily petrified despite his speed.
* Summoned wolves will be targeted by Split Shot or Mystic Snake
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.
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).
Lycan
* Heroes who do not have nor rely on passive abilities make Nethertoxin much less effective: Clinkz, Pugna, Nature's Prophet, Dark Seer, Lycan, Tusk
Lycan
* 
Arctic Burn allows Winter Wyvern to escape Lycan, even when he uses his ultimate.
* 
Splinter Blast is very effective in dealing with Lycan's summons.
* 
Cold Embrace saves allies from Lycan's raw physical damage and can buy allies enough time to turn the tide of battle.
* 
Winter's Curse stops Lycan in his tracks and is very effective because of his summons.
Additional:
* All of Lycan's damage is physical which is totally negated by Cold Embrace.
* Lycan often moves around with large amount of creeps, wolves created by Summon Wolves and neutral creep dominated by 
Helm of the Dominator which can be easily cleared by Splinter Blast or used as a great source of damage by Winter's Curse. If you catch Lycan with creeps nearby and affected by Shapeshift using Winter's Curse on him will most certainly end up with his death.
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.
Lycan
* Kraken Shell grants him massive physical attack protection
* 
Anchor Smash will wipe the area, clearing Lycan's wolves.
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.
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.
Lycan
* Void's slow is useless against Lycan by activating Shapeshift.
* Night Stalker's single target abilities (with the exception of Void upgraded by Aghanim's Scepter) is not very effective against Lycan's Summon Wolves during the early and mid game.
Lycan
* Rupture completely negates Lycan's high mobility.
Rupture completely negates Lycan's high mobility.
Bloodrage.
* All of Lycan's summons are good sources of healing with Bloodrage.
Additional:
*
* All of Lycan's summons are good sources of healing with
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.
Pounce.
Dark Pact cannot dispel Rupture, preventing Slark from escaping ganks.
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.
* Rupture will deal damage during
*
Additional:
*
*