* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: Tidehunter, Bristleback, Slardar.

* Heroes who can stun multiple units at once: Dark Willow, Spirit Breaker, Slardar, Invoker, and Tidehunter.

* 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.

* Once you get a Black King Bar, squishy spellcasters like Zeus, Skywrath Mage and others will be probably easy to deal with.

* Heroes with haste can negate Enchant's slow: Weaver, Dark Seer, Lycan, Centaur Warrunner.

* Heroes with single-target abilities will be overwhelmed by Lycan and his summons: Wraith King, Bane, Phantom Assassin.

* 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

* 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.

* Corrosive Haze hinders Nyx Assassin's ganking attempts with Vendetta, as well as reducing his armor and make him very vulnerable due to his low health pool.
* Guardian Sprint allows Slardar to catch up with Nyx Asssassin and finish him off if he has vision over him.

* 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.

* While Slardar has Guardian's Sprint activated, Powershot cannot slow him and is easier to avoid.
* Slithereen Crush and Bash of the Deep help Slardar put Windranger in place, even when she uses Windrun to escape.
* Corrosive Haze from Slardar is very effective against Windranger's already low armor. This becomes even worse if she has Aghanim's Scepter-upgraded Windrun, because it also reveals her position and allowing his allies to use their abilities on Windranger.
* Note that the invisibility provided by Aghanim's Scepter-upgraded Windrun is not broken upon attacking, casting abilities or using items, so it's vital to cast Corrosive Haze beforehand.

* 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.

* Slardar can use Guardian Sprint with Blink Dagger or Shadow Blade to get close, and Slithereen Crush will stun Sniper and slow him, making him vulnerable to Slardar's teammates.
* Corrosive Haze lowers Sniper's armor and makes Sniper's Shadow Blade useless, easily killing him with a few attacks.

* You can easily kill a squishy Sniper, due to your high movement speed and his lack of escape.

* Slardar's Slithereen Crush allows him to stun Spectre and illusions, and Corrosive Haze prevents her from juking with Spectral Dagger.

* 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.

* Heroes with spells that negate invisibility such as Bounty Hunter, Zeus and Slardar prevent her from saving her allies with Moonlight Shadow.

* Mirana's Leap is ineffective if Lycan uses Shapeshift. It also allows him to dodge Sacred Arrow.

* Corrosive Haze and Bash of the Deep will make short work of Huskar's low armor, even if Slardar is alone.

* Heroes with low armor and little mobility, like Huskar, Io, etc. will also have an unfortunate fate.

* Heroes who can provide True Sight are always credible threats: Slardar, Bounty Hunter, especially Zeus since his Lightning Bolt provides True Sight without the need to detect her beforehand to apply the debuff. So even a late-coming Zeus can easily scout a large area to reveal her, and she cannot purge herself from his sight with the dispel talent.

* 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

* Heroes with high physical damage can damage Lifestealer more than he can heal: Bristleback, Clinkz, Luna,Shadow Fiend, Slardar, Terrorblade

* Heroes with summons: Lycan, Broodmother, Visage, Nature's Prophet, Warlock.

* 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.

* 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.

* 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.

* Corrosive Haze works much like Track, giving the enemy team vision over Riki. While it doesn't give a movement speed or gold bonus, it instead can melt Riki's armor and Slardar can use Guardian Sprint to catch up to him.
* Slardar's Aghanim's Shard, causes Slithereen Crush to apply Corrosive Haze even if Slardar does not have vision over him.
Additional:
* Corrosive Haze makes Riki completely vulnerable to Slardar and his allies, as Riki has no easy way of dispelling it.
* Slardar's physical damage with Slithereen Crush and Bash of the Deep amplified by Corrosive Haze can easily kill Riki.

* Shadow Fiend, a normal Shadow Blade builder often relies on its invisibility to escape fights. Corrosive Haze reveals Shadow Fiend and also weakens his already low armor.

* Weaver relies on Shukuchi to escape and kite enemy heroes. Slardar's Corrosive Haze lowers armor and reveals Weaver, who is already a very frail target.
* Weaver usually builds Linken's Sphere, Corrosive Haze can be used to pop the spell block, additionally the level 25 undispellable talent will prevent Weaver from removing Corrosive Haze with Time Lapse, allowing allied heroes to use their abilities on Weaver.
Additional:
* Corrosive Haze lowers armor and reveals Weaver during Shukuchi, who is already a frail target. In addition, Weaver usually builds Linken's Sphere, and Corrosive Haze can be used to "pop" the spell block. His level 25 talent can also make Corrosive Haze undispellable by Time Lapse, which puts Weaver in an even worse situation.
* Guardian Sprint can dodge Weaver's bugs with the movement speed bonus.

* Corrosive Haze reveals Pudge's location, making it hard for him to use Meat Hook from the fog of war on Slardar's teammates or Slardar himself.
* Slithereen Crush interrupts Pudge while he is using Dismember.
* Guardian Sprint allows Slardar to avoid Meat Hook.
Additional:
* While Slardar has Guardian Sprint activated, Rot cannot slow him and Meat Hook is easier to avoid.
* Slithereen Crush allows Slardar to interrupt Dismember at close range (when Slardar is not a target).
* Corrosive Haze reveals Pudge's location, making it very difficult for him to land hooks from the fog.

* 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.

* Corrosive Haze followed by Slithereen Crush takes advantage of Alchemist's main weakness, being physical damage before he has the change to improve his surviability with items.
* Bash of the Deep will deal lots of damage during the laning phase.

* 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.

* 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.

* 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.

* Shapeshift allows Lycan to chase down Earth Spirit.

* Slardar can reveal Clinkz with Corrosive Haze and make him easy to kill, and his Bash of the Deep also hits hard against Clinkz's naturally low health pool.
* Slardar's Guardian Sprint can catch up with Clinkz's Skeleton Walk.
* The stun and slow from Slardar's Slithereen Crush can hold Clinkz in place.
Additional:
* Clinkz survivability depends entirely on Skeleton Walk. Corrosive Haze not only makes its invisibility useless, but also makes Clinkz even more vulnerable to physical damage.

* 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.

* Corrosive Haze provides True Sight on its target, exposing Bounty Hunter's position regardless of Shadow Walk.
* Guardian Sprint gives a very high movement speed bonus, allowing him to chase Bounty Hunter even if Slardar is tracked.
Additional:
* Bounty Hunter's Shadow Walk is rendered useless with Corrosive Haze and makes Bounty Hunter an easy target for Slardar and his team.

* Slardar deals entirely physical damage. He does not have to worry about Counterspell.
* Slithereen Crush and Bash of the Deep prevent Anti-Mage from using Blink, the latter even if Anti-Mage activates Black King Bar.
* Corrosive Haze allows allies to take down Anti-Mage before he has a chance to Blink, and maintains vision over him even if he does Blink away.
Additional:
* Slithereen Crush and Bash of the Deep deals physical damage, bypassing the magic resistance bonus from Counterspell
* Corrosize Haze significantly increases the damage dealt against Anti-Mage, and makes it harder for him to flee with Blink, although Anti-mage can block its casting with with Counterspell

* 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.

* 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.

* Heroes who do not have nor rely on passive abilities make Nethertoxin much less effective: Clinkz, Pugna, Nature's Prophet, Dark Seer, Lycan, Tusk

* Heroes who can provide True Sight or semi-reveal enemy heroes as Nature's Prophet is prone to buying Shadow Blade: Bounty Hunter, Slardar, Spectre, Zeus, Spirit Breaker.

* 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.

* Crystal Maiden's already low armor and easily interruptible ultimate, Freezing Field can make Slardar her worst nightmare. Crystal Maiden also often builds Glimmer Cape which is revealed by Corrosive Haze.

* Slardar can attack through Plague Wards and gain Bash of the Deep charges, and Templar Assassin can spill Psi Blades through Plague Wards too.

* Once you get a Black King Bar, squishy spellcasters like Zeus, Skywrath Mage and others will be probably easy to deal with.

* Heroes with single-target abilities will be overwhelmed by Lycan and his summons: Wraith King, Bane, Phantom Assassin.

* Bounty Hunter and Slardar both have ultimates (Corrosive Haze and Track) that reveal Invoker through Ghost Walk.

* 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.

* Heroes with armor reducing abilities greatly hinder Visage's defense like Slardar and Dazzle.

* Heroes with single-target abilities will be overwhelmed by Lycan and his summons: Wraith King, Bane, Phantom Assassin.

* Corrosive Haze will reveal Treant Protector even when he is under the effects of Nature's Guise.

* The brutal physical damage of Slithereen Crush and Bash of the Deep can quickly remove Void Spirit's shield and stun him for a while.
* Corrosive Haze provides vision of Void Spirit while he is running away and Guardian Sprint allows Slardar to quickly close the gap

* 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.

* With armor items like Solar Crest or Assault Cuirass combined with Bash of the Deep, Slardar can easily tank the Duel, If not dueled himself, he can drop Legion Commander's armor during duel and/or buff his teammate and save them, leaving her only the choice of dueling supports which can also be saved with fast Blink into Slithereen Crush.

* Heroes with abilities that can close the gap can easily kill Muerta: Storm Spirit, Earth Spirit, Ember Spirit, Void Spirit, Lycan, Chaos Knight, Tusk.

* Slardar can chase Dragon Knight down with Guardian Sprint and stun him with both Slithereen Crush and his passive Bash of the Deep. He can also use Corrosive Haze to whittle Dragon Knight's armor.

* 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.

* Heroes with hastes: Dark Seer, Lycan

* Slardar's level 25 talent makes Corrosive Haze undispellable, thus providing his allies vision of Slark.

* Guardian Sprint allows Slardar to outrun Bristleback, even when slowed by Viscous Nasal Goo.
* Corrosive Haze's armor reduction makes Bristleback much less tanky.