* Riki is known for being a successful support killer, and not just for show. He can give you one hell of a time by constantly picking you off and/or forcing you to stick close to the rest of the team.
* Smoke Screen is particularly devastating to Shadow Shaman. With neither his various disables nor a solid health pool Shadow Shaman is usually dead. Consider a force staff if you find yourself in this scenario (to force yourself out of the cloud before shackling Riki) and buy sentry wards if you have the money.

* He won't be around waiting for Medusa to Stone Gaze and pin him until she bears a true sight.
* With Smoke Screen, Riki will silence and catch Medusa in a surprise with high miss chance flushing her from positions easily in team fights.
* He can still deal huge amount of damage through Cloak and Dagger via backstabs, drying out Medusa's protection in a whim at random occassions.

* With her passive Split Shot, Medusa can be easily interrupted by Spiked Carapace during combat, especially during her precious Stone Gaze.
* Mana Burn quickly destroys Mana Shield, especially if Medusa only increases her mana pool by bolstering intelligence (which has the added bonus of increasing Mana Burn's damage).
* Uncontrollable damage from Mystic Snake and Split Shot can trigger Spiked Carapace.
* Medusa lacks single target damage, making a Burrowed Nyx Assassin hard to kill.
Additional:
* Level 4 Mana Burn burns 38,5% of Medusa's mana every 4 seconds if Medusa only increases her mana pool with intelligence. Additionally, 60% of the Mana Burn damage gets mitigated by Mana Shield, burning even more mana.
* Due to the passive nature of Mystic Snake and Split Shot, it can possibly proc Nyx's Spiked Carapace if he's within range of Medusa's abilities and isn't invisible.
* Medusa lacks single target damage, making Nyx with Aghanim's Scepter extremely hard to deal with if Medusa is the team's main damage source.

* 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.

* Arc Warden with his Magnetic Field will protect allies from Mass Serpent Ward.

* Unlike other illusion heroes, Tempest Double won't be instantly destroyed by Stone Gaze since it is considered a clone and not an illusion.
* He can use either his own or his double's Flux to bypass the spellblock from Linken's Sphere, using the leftover Flux + Spark Wraith to slow Medusa's move speed to a crawl.
* Arc Warden has a farming advantage with double Hand of Midas, and can generally bully Medusa with other items that benefit from duplication.

* Webbed areas can be used to hit and run, covering distance hastily weakening her on the way and initiating ganks.
* Even though Medusa can hunt down Spiderlings easily when given enough range, after an Incapacitating Bite she will get her swarmed in no time.
* Medusa usual do not build a BKB to benefit from Mana Shield fully while Broodmother can fit a Diffusal Blade to burn away mana.
Additional:
* Incapacitating Bite will give Medusa a dire time to clear horde of small spiderlings or retaliate Broodmother herself.
* Spin Web will allow broodmother to pick her own fights and sometimes slip away to ambush Medusa.

* Support heroes with low mobility can be slowed further by Incapacitating Bite, and swarmed by Spiderlings for an easy kill: Shadow Shaman, Visage, Dazzle, Rubick, Lich.

* Other heroes with mana burning or manipulating abilities will make Medusa much less tanky: Lion, Mirana, Weaver.

* Mirana can disturb your channeling even if you are under the effect of invisibility thanks to Sacred Arrow.
* Mirana armed with an Aghanim's Scepter is known to be able to quickly burst down heroes - especially supports. Together with Ethereal Blade the bullying can continue for the whole match.

* With 4 active abilities, Shadow Shaman is weak against silencing foes such as silencer, Drow Ranger and Death Prophet.

* Silencer burns easily through her effective hp from Mana Shield, by taking away her int.
* Arcane Curse punishes her repeatedly casting Mystic Snake to keep her mana pool high. Can force her to use Manta Style before he has cast Global Silence and Medusa usually does not want to build Black King Bar.

* Medusa is a fairly immobile hero that deals damage around her with Split Shot. Sniper should outrange her and should stay out of harm's way from Split Shot.
* More importantly, Sniper should have enough attack range to fire at Medusa during her Stone Gaze without turning to stone, so the ultimate is mostly wasted against him.
Additional:
* Sniper can outrange both Medusa's arrows and Stone Gaze, allowing him to focus her down during a teamfight.

* Heroes with channeled abilities which Assassinate may cancel at long range: Witch Doctor, Crystal Maiden, Shadow Shaman, Pugna

* 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.

* 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 removes 1 of every attribute, lowering Medusa's mana pool's cap and leaving her much more vulnerable in prolonged fights.
Additional:
* 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.

* Heroes that build Diffusal Blade or can fit it well into their item build will also make Medusa much less tanky: Riki, Naga Siren, Terrorblade, Juggernaut, Spectre, Slark,Drow Ranger.

* With 4 active abilities, Shadow Shaman is weak against silencing foes such as silencer, Drow Ranger and Death Prophet.

* Fiend's Grip provides mana drain, which can heavily damage Mana Shield and prevent Medusa from using Stone Gaze.
* Even if she does use Stone Gaze, Nightmare can buy enough time to protect allies and reset the fight.
Additional:
* His Fiend's Grip will leave Medusa defenseless after he's done, if his teammates can provide cover for him or he initiates at the right time by Spell immunity.

* Nether Ward will cause an unfriendly area for Medusa, draining her mana.

* 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.
Additional:
* Ursa's status resistance from Enrage will ignore Medusa's gaze.
* Ursa can stack damage with Fury Swipes easily against her Mana Shield in a prolonged team match.

* Phantom Lancer with Diffusal Blade will very quickly burn Medusa's mana, making Mana Shield significantly less effective.
* Doppelganger's 1 second invulnerability can be used to dodge Medusa's petrification from Stone Gaze, as well as Mystic Snake.
* Phantom Lancer's illusions outnumber Medusa's targets from Split Shot, likely shielding your team in the process.

* Reincarnation allows Wraith King to survive Shadow Shaman's initial chain of disables and Serpent Ward attacks.
* Short cooldown of Wraithfire Blast is ideal for interrupting Shackles.

* Medusa lacks mobility or escape mechanisms. Earth Spike and Hex can neutralize her strong damage potential and allow for Lion's team to focus her down.
* In addition to easily breaking her commonly bought Linken's Sphere with its low cooldown, Mana Drain can quickly drain her Mana Shield, making her far less tanky.

* As a caster, Anti-Mage's Mana Break and Mana Void are highly effective against him.

* Anti-Mage easily destroys Mana Shield with Mana Break, especially once he has Manta Style.
* Anti-Mage effectively avoids Stone Gaze with Blink, and can reinitiate after its duration is over.
Additional:
* Anti-Mage's Mana Break burns Medusa's mana easily, especially when coupled with a Manta Style.
* Can easily initiate on Medusa with Blink, burning her mana or forcing her to use Stone Gaze.
* Mana Void is effective against Medusa's big mana pool and mana usage, presenting a huge hazard to Medusa's allies around her since her Mana Shield still gives her some protection if she has mana.

* Dragon Knight can simply tank and destroy all Shadow Shaman's Serpent Wards.

* Waveform allows Morphling to escape from Mass Serpent Ward
* Morphling can interrupt Shadow Shaman while he is shackling an ally with Adaptive Strike (Strength).
* With Ethereal Blade Morphling can quickly burst him down before he even has a chance to react.

* Because of her need to get status items early to tank it up, Rubick can greatly reduce her damage early with Fade Bolt
* Her stationary nature and the slow cast time of her spells makes it easier for Rubick to steal Stone Gaze or Mystic Snake
* Aghanim's Scepter's Mystic Snake is often better used by Rubick than by Medusa

* Chakra Magic can drain her current mana, draining away her effective health in a sneaky way.
* Will-O-Wisp will keep Medusa busy after she got hit by Blinding Light.

* 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.

* Heroes that build Diffusal Blade or can fit it well into their item build will also make Medusa much less tanky: Riki, Naga Siren, Terrorblade, Juggernaut, Spectre, Slark,Drow Ranger.

* Heroes that build Diffusal Blade or can fit it well into their item build will also make Medusa much less tanky: Riki, Naga Siren, Terrorblade, Juggernaut, Spectre, Slark,Drow Ranger.

* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.

* Omniknight can dispel Hex or Shackles with Heavenly Grace. He can also heal teammates which you disabled. The same goes to Abaddon's Aphotic Shield .

* With 4 active abilities, Shadow Shaman is weak against silencing foes such as silencer, Drow Ranger and Death Prophet.

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

* Heroes who take a long time to become strong are in for a rough mid game, such as Outworld Destroyer, Magnus, Medusa, and Anti-Mage.

* Omniknight can dispel Hex or Shackles with Heavenly Grace. He can also heal teammates which you disabled. The same goes to Abaddon's Aphotic Shield .

* Pudge, Legion Commander and Axe will make the match a living hell for you, since they are known for surprise attacks from the fog and quickly killing low HP heroes. They can also interrupt your channeling, Legion being especially problematic, as she can use Press the Attack on an ally who is hexed as well.

* Lone Druid's early game is good against slow, squishy supports since his bear is very strong early game and an Entangling Claws proc almost always guarantees a kill: Ancient Apparition, Crystal Maiden, Shadow Shaman, Skywrath Mage etc.

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

* Shadow Shaman has no effective burst damage, thus Chen has a lot of time to save an ally with his creeps or Hand of God from a gank.
* Chen can use {U:Centaur Conqueror} or {U:Mud Golem} to interrupt Shadow shaman's Shackles channeling
* Mass Serpent Ward can be easily teared down by Chen's creep army

* EMP is a large mana burn nuke which can hit Medusa's Mana shield with enough damage to lose even more mana.
* Deafening Blast disarms Medusa's ability to deal pseudo-AOE damage during teamfights.
* Cold Snap allows the opposing team to repeatedly stun Medusa in short succession, preventing her from successfully casting her ultimate due to its long cast time.
Additional:
* EMP allows Invoker to burn Medusa's mana to weaken Mana Shield.
* Medusa's lack of mobility makes her easy to kite with Invoker's spells.