* Dark Pact can be used to remove Open Wounds.
* Shadow Dance allows Slark to attack Lifestealer for its duration without any way for Lifestealer to fight back.
* Slark commonly buys a Silver Edge, which can break Lifestealer's Feast, severely diminishing his damage output and lifesteal.

* Lifestealer's low mobility makes him easy to kite.
* Stone Gaze pierces Rage, wasting its cooldown and making Lifestealer unable to fight.

* Split Shot will keep attacking Pangolier even when he is rolling around.
* Stone Gaze stuns Pangolier during Rolling Thunder, or forces him to roll away.

* Dark Pact easily purges away both slow and disarm effect from Lucky Shot.
* With Pounce now apply 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.

* Enchantress often has a small army of neutral creeps, allowing Medusa to hit her with a later bounce of her Mystic Snake.
* Untouchable is ignored by secondary attacks from Split Shot.

* Heroes that can jump on her: Slark, Queen of Pain, Anti-Mage

* If Medusa activates Stone Gaze, the charge will inevitably fail.
* Mana Shield and overall tankiness allows Medusa to easily survive Spirit Breaker's initiation.

* 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.

* Her Mana Shield is too tough for Lycan to break in.
* 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

* Lycan cannot escape from a Pounce even if he uses Shapeshift, and has no disabling abilities to stop Slark.

* Enigma is fragile, and lacks escapes, being dependent on Blink Dagger for mobility. Ganking Heroes or Heroes with burst damage will likely kill him before he can do anything. Such Heroes include: Lina, Lion, Puck, Slark, Nyx Assassin, etc.

* Medusa's Split Shot can make quick work of Enigma's Eidolons and take advantage of their considerable bounty.
* If Medusa activates Stone Gaze at the start of a fight, it can make initiating — and landing an effective Black Hole exceedingly difficult.
* Mystic Snake can be potentially detrimental to Enigma's initiation. Getting hit by the latter high-damage bounces (from standing behind his Eidolons or his teammates) can hinder his mana pool, preventing him from executing a strong initiation.
Additional:
* Mana Shield makes Medusa harder to kill with Enigma's Black Hole and Pulse combo.
* Medusa's Split Shot can kill Demonic Conversion creeps easier and Mystic Snake bounces off from them.
* Stone Gaze makes it hard for Enigma to approach Medusa for a Black Hole.

* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.

* Heroes with strong dispels can remove Primal Roar's stun: Abaddon, Slark, Oracle.

* 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.

* 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.

* Dark Pact dispels Dismember if timed perfectly.
* Pudge's low attack speed and poor agility can be lowered even further by Essence Shift.
* Shadow Dance grants Slark invisibility and a high degree of mobility, which can make Slark a difficult target to hook and also protects him from Pudge's Dismember (including allies with an Aghanim's Scepter).

* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with Phantom Strike.
* As a hero who always goes for the Silver Edge and Abyssal Blade Slark can use it to disable Phantom Assassin and her Blur and Coup de Grace, drastically reducing her damage output and ability to evade attacks, and also preventing her from acting.
* Phantom Assassin's Coup de Grace requires Random Number Generation in order to proc, which gives Slark more than enough time to escape and recover himself.

* Arctic Burn and Splinter Blast debuffs are dispellable with Dark Pact. Arctic Burn is also no escape against Pounce.
* Cold Embrace just gives Slark free Essence Shift stacks. He also relies mostly on magic damage early in the game.

* 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.

* 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.

* Mana Shield makes Medusa very hard to take down in Duels.
* Stone Gaze stops Legion Commander from Dueling altogether, regardless of who she targets.

* 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.

* Stone Gaze allows Medusa to easily kite and kill Sven.
* Mystic Snake eats away at Sven's small mana pool.
* Mana Shield negates much of Sven's burst damage.

* Summoned gargoyles will give Medusa free target practice.
* Mana Shield will resist Soul Assumption instances without effort.

* 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.

* Split Shot can destroy Tombstone Zombies and Tombstone itself while still damaging heroes.
* Mana Shield reduces the impact of Decay and Flesh Golem's Plague Aura.

* 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.

* 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.

* Dark Pact can dispel Venomous Gale and Poison Sting.
* Shadow Dance allows Slark heightened regeneration when out of vision making DoTs effects less threatening.

* Mana Shield tanks most of the damage from Reaper's Scythe; with sufficient mana, the kill threshold drops to 15%/17%/19% health (before reductions).
* Heartstopper Aura does not chip away at Medusa's mana, this makes it not a threat as it deals damage based on current health.
* Necrophos has a movement speed equal to Medusa, and is easy to chase down with a slowing item in Medusa's inventory.

* Stone Gaze negates Dispersion's damage reduction and allows Medusa to kite Spectre.
* Spectre's small mana pool is depleted quickly by Mystic Snake.
* Split Shot can clear Haunt illusions quickly.

* Heroes with good escapes can usually outmaneuver and escape from Spectre: Slark, Clinkz, Weaver

Additional:
* 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 from or chasing 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.

* Pounce also stops Nature's Prophet's Teleportation.

* 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.

* 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.

* Heroes with cleave abilities and area of effect damage can make quick work of Chen's converted creeps and at same time gain farm: Magnus, Jakiro, Shadow Fiend, Kunkka, Luna, Dragon Knight, Medusa, Alchemist.

* 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.

* 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.

* Weak damage but high tick rate or persist in a long time: Slark, Gyrocopter, Queen of Pain, Shadow Shaman (Shackles), Pugna
* 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), Pugna

Additional:
* 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.

* 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.

* Nyx Assassin, Bounty Hunter and Slark can all sneak up and kill you, Nyx being particularly deadly. Watch Slark carefully, as he can break either (but not both unless you are making a mistake) of your 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 you from prey to predator.

* 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.

* Heroes who have a high mobility (Queen of Pain, Storm Spirit, Slark, etc.).

* Poof won't damage Medusa and he can Gaze an entire flock of Meepos.
* Mystic Snake will easily become the bane of Meepo early game.

* 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.

* Doom does not disable Mana Shield. As such, Doom's damage is largely mitigated by her mana shield. Additionally, Medusa is not reliant on her abilities to be effective during a teamfight, making Medusa an unproductive hero to target.
* Medusa is an ideal Linken's Sphere carrier. Should one be purchased, and without any additional disables, Doom may find that few opportunities exist to effectively lockdown, disable, and kill Medusa.

* Shadow Dance prevents Luna from damaging Slark, and together with Shadow Blade he can kite her or escape.
* Luna has no way to escape from Pounce's leash.
Additional:
* Luna's lack of mobility and escape abilities makes her easily gankable by Slark.
* Shadow Dance will avoid all the damage from Eclipse.
* For the same reasons, Slark is a good ally for Luna when they are in the same team.

* 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.

* 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.

* 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.

* A well-timed Dark Pact can dispel Frost Arrows and Gust, letting Slark engage and escape freely.
* Shadow Dance lets Slark quickly close the gap and deal heavy damage without giving Drow Ranger a chance to retaliate.
* Pounce counteracts Frost Arrows' slow, letting Slark easily pin Drow Ranger down or flee.
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.

* Heroes who can dispel will be able to remove Shadow Poison before Shadow Demon can build up a big stack, or remove Soul Catcher's debuff to instantly bring the health of affected heroes back to a considerable amount: Abaddon, Slark, Legion Commander, Oracle.

* Slark is a natural Shadow Blade carrier, and with Pounce Sniper has no opportunity to escape or react.
* With Essence Shift and Shadow Dance, Slark will easily win a fight against Sniper.
Additional:
* Sniper is one of the most gankable heroes in the game, and has no defenses when Pounced on by 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.

* Pounce and Dark Pact together with some attacks can gank Rubick down quickly. Rubick can seldom retaliate because of the strong dispel of Dark Pact. What is more, Rubick is the type of squishy support that Slark exactly wants to gank.
* Though Shadow Dance is a great spell to steal, Slark's untargetable nature and his low cooldown spells prevents Rubick from stealing it.
* Slark usually builds Diffusal Blade which can prevent Rubick to cast his abilities from Spell Steal.

* Mystic Snake can harass Axe in lane and drain his small mana pool.
* Mana Shield reduces the effectiveness of Counter Helix.
* Stone Gaze makes it very difficult for Axe to pursue.

* Heroes with invisibility and high mobility can jump on and focus down Earthshaker before he has a chance to initiate: Clinkz, Slark, Storm Spirit

* Medusa cares less than other heroes about armor reduction, since Mana Shield blocks 70% of all damage without taking armor/magic resistance into consideration. This makes 60% of your Corrosive Haze ineffective until Medusa's mana is drained.

* Heroes with escaping and disjointing abilities can be good against Juggernaut: Riki, Queen of Pain, Puck, Storm Spirit, Ember Spirit, Slark etc.

* 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.

* Mana Shield makes it very difficult for Bloodseeker to gain his Thirst bonuses.
* Rupture rarely kills Medusa through Mana Shield.

* 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.

* 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.