Medusa
* 
Vendetta burns a significant amount of mana on hit, and the damage from the ability drains Medusa's mana pool even further.
* 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.
Additional:
* 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.
Dark Willow
* Nyx Assassin's high burst damage can be the bane of Dark Willow, as her low health makes it difficult to survive long enough to escape through Shadow Realm.
* Spiked Carapace can be triggered by walking deliberately into Bramble Maze, leaving Dark Willow stunned and defenseless.
Medusa
* 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:
* 
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.
Dark Willow
* 
Counterspell negates Dark Willow's high magic burst damage. Its active blocks 
Cursed Crown.
* Blink allows Anti-Mage to dodge Terrorize during its long cast animation, as well as avoiding the obstacles from Bramble Maze. On the other hand, if Anti-Mage gets caught inside Bramble Maze, he's unable to Blink away.
* Dark Willow's chained magic burst requires a lot of mana, setting her up for damaging Mana Voids.
Medusa
* 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 already low 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.
Dark Willow
* 
Magnetic Field lets Arc Warden or allies evade Dark Willow's shadow realm attacks. The duration of the evasion can be extended with the clone.
* Spark Wraith also exploits Dark Willow's low mobility.
Medusa
* 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 deal a huge amount of damage through 
Cloak and Dagger, even through Mana Shield.
Dark Willow
* Smoke Screen prevents Dark Willow from using her abilities, rendering her defenseless and unable to deal any serious damage.
* 
Blink Strike lets Riki jump past Bramble Maze.
Medusa
* 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.
Dark Willow
* 
Blade Fury dispels most of Dark Willow's abilities, allowing Juggernaut to pass through Bramble Maze and cancel out Cursed Crown before the stun occurs.
* However, Dark Willow can tank 
Omnislash with 
Shadow Realm. As she is a valid target, but invulnerable to right clicks.
Additional:
* None of Dark Willow's spells pierce Spell Immunity, making Blade Fury a good counter against her. Additionally, it dispels Cursed Crown and 
Bramble Maze.
* Dark Willow is generally fragile, which results in Omnislash being devastating against her.
* However, if Shadow Realm is activated during Omnislash, then the attack damage is negated (though Omnislash can still jump to other enemies).
Medusa
* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: 
Tidehunter, 
Bristleback, 
Slardar.
Dark Willow
* 
Quill Spray's constant AoE damage will hit Dark Willow even in Shadow Realm. Its automatic damage will hurt her if she tries to get close and use Bedlam.
Medusa
* 
Burning Spear's damage over time can rapidly burn Medusa's mana and health alike.
* 
Inner Fire can slow and disarm Medusa and also allow Huskar to follow up with Life Break.
Dark Willow
* 
Fortune's End not being disjointable is almost an ensured disable if Dark Willow tries to escape with Shadow Realm. Dispels Cursed Crown and Terrorize.
* 
Fate's Edict negates all her magic damage in case she catches a single hero.
* 
False Promise's strong dispel removes Dark Willow's disables.
Additional:
* Fortune's End can easily dispel Cursed Crown before it times out and stuns. He can also save a stunned ally with False Promise.
* Fate's Edict can easily negate 
Bedlam's over-time damage, since the spell provides no form of control. Similarly, he can also negate the magic burst from Shadow Realm.
* Fortune's End can dispel the fear effect from 
Terrorize, and it can remove the root from Bramble Maze if cast quick enough. Be mindful that Fortune's End only dispels your allies' debuffs on the primary target.
Medusa
* 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:
* 
Fiend's Grip leaves Medusa defenseless, since not only does it deal damage, it also drains mana.
Medusa
* 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, 
Silken Bola will cause her attacks to miss and get her swarmed in no time.
* Medusa usually does not build a Black King Bar to benefit from Mana Shield fully while Broodmother can fit a Diffusal Blade to burn away all of Medusa's mana.
Additional:
* 
Spin Web will allow Broodmother to pick her own fights and sometimes slip away to ambush Medusa.
* Though Medusa's Split Shot and Mystic Snake can help Medusa deal with Broodmother's spiderlings, Broodmother will create too much of them for her to handle, allowing her to outnumber Medusa's targets from Split Shot and shield her team in process.
Medusa
* E.M.P. 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.
Additional:
* 
E.M.P. 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.
Dark Willow
* 
Gust can hit Dark Willow beyond a defensive Bramble Maze, and before she gets close enough to hit Drow Ranger with Bedlam.
* Drow Ranger's long range allows her to hit Dark Willow's team without venturing into her Bramble Maze.
Medusa
* Ursa's status resistance from 
Enrage reduces duration of Medusa's Stone Gaze.
* Ursa can stack damage with 
Fury Swipes easily against her Mana Shield in a prolonged team match.
Additional:
* Medusa's tankiness doesn't help her very much against Fury Swipes in long teamfights.
* With no escape mechanism and a slow movement speed, getting jumped on by Ursa usually spells a quick end for Medusa in the early game.
Medusa
* Axe can take advantage of Medusa's awfully low HP to insta-kill her with 
Culling Blade, making it extremely difficult for her to farm for items to compensate for the lack of strength during early and mid-game while Axe is continuously harassing around.
Dark Willow
* 
Berserker's Call forces Dark Willow to attack, cancelling Shadow Realm.
Medusa
* Mana Shield reduces the effectiveness of Counter Helix.
* Stone Gaze makes it very difficult for Axe to initiate on Medusa and her allies.
Dark Willow
* All of Puck's abilities are area-targeted, and will hit Dark Willow when she uses Shadow Realm.
* 
Illusory Orb allows Puck to bypass Bramble Maze, close the gap and silence Dark Willow with 
Waning Rift.
* 
Phase Shift helps Puck dodge attacks charged by Shadow Realm, and is easily timed against Terrorize's long cast time.
Medusa
* 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.
* 
Mana Drain is a perfect ability to weaken Medusa's durability as it can quickly drain her Mana Shield, making her far less tanky. Mana Drain can also be used to restore mana of Lion's allies, which can nullify the mana steal from Mystic Snake.
* Mana Drain, along with Hex, destroy illusions instantly, which may be extremely helpfull and efficient against core builders of Manta Style, like Medusa herself.
Dark Willow
* Jakiro's area of effect abilities can hit Dark Willow even while she is hidden during the Shadow Realm.
* Waiting about 2 seconds after Dark Willow casts Shadow Realm to cast Ice Path will stun her while her Shadow Realm is at it's maximum damage.
* Jakiro can stun Dark Willow when there is about 1 second left on Cursed Crown, Jakiro's Ice Path stun lasts slightly longer then Cursed Crown.
Dark Willow
* 
Ancient Seal instantly shuts down Dark Willow's abilities, rendering her defenseless against his high burst damage spells, while she cannot cast spells of her own.
* 
Mystic Flare deals immense burst damage in an area, damaging Dark Willow through Shadow Realm.
Dark Willow
* 
Rot and 
Meat Hook hits Dark Willow even when she uses Shadow Realm.
* 
Flesh Heap reduces Dark Willow's magic burst damage.
Medusa
* 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.
Dark Willow
* 
Flame Guard blocks Dark Willow's magical burst damage, and harms her if she tries to get close to attack with Bedlam.
* 
Sleight of Fist and 
Fire Remnant makes it hard for Dark Willow to fully disable Ember Spirit.
Dark Willow
* 
Ball Lightning allows Storm Spirit to bypass Bramble Maze into the backline, and zip back into battle if he gets hit by Terrorize.
Medusa
* Sniper can outrange both Medusa's arrows and Stone Gaze, allowing him to focus her down during a teamfight.
Additional:
* 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.
Medusa
* With 
Static Link, Razor can effectively make Medusa useless in teamfights by reducing her main damage output. It can, however, be blocked by a 
Linken's Sphere.
* 
Plasma Field allows Razor to get on top of Medusa, slowing her already slow movement speed to a mere crawl.
* 
Eye of the Storm capitilizes on Medusa's low armor and causes her to be very vulnerable, even through Mana Shield.
Medusa
* 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 his team in the process.
Dark Willow
* Heroes with high burst damage and 
Black King Bar can take down Dark Willow quickly: 
Phantom Assassin, 
Sven, 
Wraith King
Medusa
* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: Tidehunter, Bristleback, Slardar.
Medusa
* 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.
Dark Willow
* Heroes who can silence will shut down Dark Willow entirely: 
Death Prophet, 
Silencer, 
Drow Ranger
Medusa
* Heroes with extremely slow movement speed will cripple against Solar Bind: Medusa, 
Viper
Additional:
* 
Will-O-Wisp will keep Medusa busy after she got hit by 
Blinding Light.
Medusa
* 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.
Medusa
* 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.
Medusa
* If Medusa activates Stone Gaze before Spirit Breaker reaches her with Charge of Darkness, the charge will inevitably fail.
* Medusa has three ways to counter Spirit Breaker's Charge of Darkness: Stone Gaze can disable Spirit Breaker's Charge of Darkness if he faces Medusa directly. Aghanim's Scepter upgraded Mystic Snake can disable Spirit Breaker and cancel his Charge of Darkness if it hits him. And 
Cold Blooded provided by 
Aghanim's Shard that can cast a single-targeted Mystic Snake at Spirit Breaker if he uses Charge of Darkness on her.
* Mana Shield and overall tankiness allows Medusa to easily survive Spirit Breaker's initiation. And to make things worse, Spirit Breaker is not a common Diffusal Blade nor 
Disperser wielder to counter this problem at all.
* Overall, any attempt for Spirit Breaker to gank and kill Medusa will hurt him more than the other way around.
Dark Willow
* Bramble Maze stops 
Charge of Darkness in its tracks. Its very long duration means it can be used as an obstacle to block off an incoming Spirit Break during teamfights.
* Shadow Realm and Bedlam can be activated when Dark Willow sees Charge of Darkness coming, preventing Spirit Breaker from using 
Nether Strike after the initial stun.
Medusa
* Mana Shield makes it very difficult for Bloodseeker to gain his Thirst bonuses.
* Rupture rarely kills Medusa through Mana Shield.
Dark Willow
* Bramble Maze greatly hinders Bloodseeker's ability to run around in teamfights and pick off dying allies.
* Shadow Realm prevents Bloodseeker from attacking dark Willow, allowing her to safely teleport away.
Medusa
* Poof won't damage Medusa and she can use Stone Gaze to disable all of Meepo's clones.
* Mystic Snake will easily become the bane of Meepo early game.
Dark Willow
* Casting Bramble Maze on top of Meepo guarantees a root, as it is nearly impossible to leave the thorns with all of Meepo's clones.
* Terrorize and Cursed Crown offer great disables against the grouped Meepos and can prevent them from using 
Poof to escape.
Medusa
* Any long duration disables that can pierce through both, Pierce The Veil and Black King Bar are devastating against Muerta: 
Enigma's 
Black Hole, 
Dawnbreaker's 
Solar Guardian, 
Axe's Berserker's Call, Naga Siren's Aghanim's Scepter upgraded 
Ensnare and 
Reel In from Aghanim's Scepter, 
Jakiro's Aghanim's Scepter upgraded 
Macropyre, 
Bane's Fiend's Grip, 
Pudge's 
Dismember, 
Batrider's 
Flaming Lasso, 
Beastmaster's 
Primal Roar, 
Grimstroke's 
Soulbind, Medusa's Stone Gaze, Magnus's 
Reverse Polarity.
Dark Willow
* Terrorize, Bedlam and Cursed Crown can damage Muerta through 
Pierce the Veil.
* Even if Muerta has Black King Bar and Pierce the Veil active, Dark Willow can still use Shadow Realm to protect herself against the Pierce the Veil's high damage, as Muerta cannot attack her for it's duration.
Medusa
* 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 Willow
* Heroes with powerful rooting abilities will disable most of Pangolier's skills, a bonus point if it pierces spell immunity since it will also be able to stop Pangolier during his Rolling Thunder: 
Treant Protector, 
Meepo, 
Crystal Maiden, 
Dark Willow, 
Underlord, Naga Siren
Medusa
* Heroes with strong area-of-effect damaging and/or disabling abilities will be able to intercept Underlord and his team when they exit from Fiend's Gate: 
Luna's Aghanim's Scepter upgraded 
Eclipse, Dawnbreaker's Solar Guardian, Axe's Berserker's Call, 
Mars's 
Arena of Blood, Jakiro's Macropyre, 
Dual Breath and 
Ice Path, Naga Siren's 
Song of the Siren, 
Razor's Eye of the Storm and Plasma Field, 
Lina's 
Light Strike Array, 
Broodmother's 
Spinner's Snare from Aghanim's Scepter, 
Elder Titan's 
Earth Splitter and 
Echo Stomp, 
Alchemist's 
Unstable Concoction and 
Acid Spray, 
Queen of Pain's 
Sonic Wave, 
Dark Seer's 
Wall of Replica and 
Vacuum, 
Venomancer's 
Noxious Plague and 
Poison Nova from Aghanim's Scepter, 
Oracle's Fortune's End and 
Rain of Destiny from Aghanim's Shard, 
Bloodseeker's 
Blood Rite, Enigma's Black Hole and 
Midnight Pulse, 
Shadow Fiend's 
Requiem of Souls, Batrider's Aghanim's Scepter upgraded Flaming Lasso, 
Firefly, 
Flamebreak and 
Sticky Napalm, 
Ancient Apparition's 
Ice Blast, 
Sand King's 
Epicenter, 
Sand Storm and 
Burrowstrike, 
Gyrocopter's 
Call Down, 
Ember Spirit's Sleight of Fist, Death Prophet's 
Exorcism and 
Silence, 
Monkey King's 
Wukong's Command, Crystal Maiden's 
Freezing Field, 
Muerta's 
The Calling, Medusa's Stone Gaze, 
Zeus's 
Nimbus from Aghanim's Scepter. Dark Willow's Bramble Maze, 
Pangolier's 
Swashbuckle, Grimstroke's Soulbind, 
Ink Swell and 
Stroke of Fate, 
Earthshaker's 
Echo Slam and 
Fissure, 
Puck's 
Dream Coil and Waning Rift, 
Winter Wyvern's 
Winter's Curse, Magnus's Reverse Polarity.
Dark Willow
* Heroes with strong area-of-effect damaging and/or disabling abilities will be able to intercept Underlord and his team when they exit from Fiend's Gate: Luna's Aghanim's Scepter upgraded Eclipse, Dawnbreaker's Solar Guardian, Axe's Berserker's Call, Mars's Arena of Blood, Jakiro's Macropyre, Dual Breath and Ice Path, Naga Siren's Song of the Siren, Razor's Eye of the Storm and Plasma Field, Lina's Light Strike Array, Broodmother's Spinner's Snare from Aghanim's Scepter, Elder Titan's Earth Splitter and Echo Stomp, Alchemist's Unstable Concoction and Acid Spray, Queen of Pain's Sonic Wave, Dark Seer's Wall of Replica and Vacuum, Venomancer's Noxious Plague and Poison Nova from Aghanim's Scepter, Oracle's Fortune's End and Rain of Destiny from Aghanim's Shard, Bloodseeker's Blood Rite, Enigma's Black Hole and Midnight Pulse, Shadow Fiend's Requiem of Souls, Batrider's Aghanim's Scepter upgraded Flaming Lasso, Firefly, Flamebreak and Sticky Napalm, Ancient Apparition's Ice Blast, Sand King's Epicenter, Sand Storm and Burrowstrike, Gyrocopter's Call Down, Ember Spirit's Sleight of Fist, Death Prophet's Exorcism and Silence, Monkey King's Wukong's Command, Crystal Maiden's Freezing Field, Muerta's The Calling, Medusa's Stone Gaze, Zeus's Nimbus from Aghanim's Scepter. Dark Willow's Bramble Maze, Pangolier's Swashbuckle, Grimstroke's Soulbind, Ink Swell and Stroke of Fate, Earthshaker's Echo Slam and Fissure, Puck's Dream Coil and Waning Rift, Winter Wyvern's Winter's Curse, Magnus's Reverse Polarity.
Medusa
* 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.
Medusa
* Should Luna choose to buy Manta Style, Medusa will be able to kill illusions from them with Split Shot and 
Mjollnir, which is a common item on Medusa.
* Mystic Snake allows Medusa to easily harass Luna and steal mana from her, preventing Luna from retaliating with 
Lucent Beam.
* Medusa can survive Eclipse thanks to Mana Shield, which can cause Luna to struggle greatly in bursting down Medusa and force her to buy Diffusal Blade and it's upgrade Disperser.
* Even with Black King Bar, Medusa's Stone Gaze will still be able to disable Luna, which could even discourage her from counter-initiating with Eclipse.
Additional:
* Should Luna choose to buy Manta Style, Medusa will be able to kill illusions from them with Split Shot and Mjollnir, which is a common item on Medusa.
* Mystic Snake allows Medusa to easily harass Luna and steal mana from her, preventing Luna from retaliating with Lucent Beam.
* Medusa can survive Eclipse thanks to Mana Shield, and since Luna is not a hero that often goes for Diffusal Blade, she will struggle greatly in bursting down Medusa.
* Even with Black King Bar, Medusa's Stone Gaze will still be able to disable Luna, which could even discourage her from counter-initiating with Eclipse.
* For the same reasons, Medusa makes a very powerful ally for Luna when they are in the same team.
Medusa
* Medusa's Split Shot can easily kill Chen's creeps.
* Mystic Snake can quickly kill Chen's creeps and deal intense damage for every killed creep while also draining their mana with each bounce. Aghanim's Scepter upgraded Mystic Snake can also disable both, Chen and his creeps upon impact.
* Mana Shield will make it impossible for Chen to burst down Medusa.
* Stone Gaze can disable Chen from using 
Hand of God to save himself or his allies.
Medusa
* Enchantress often has a small army of neutral creeps, allowing Medusa to hit her with a later bounce of her Mystic Snake.
Dark Willow
* Bramble Maze prevents Timbersaw from 
Timber Chaining away without getting rooted.
* Cursed Crown can still catch Timbersaw if he Timber Chains away.
* 
Reactive Armor offers little protection against Dark Willow's high magical damage.
Dark Willow
* Bramble Maze will very likely catch Marci midair, disabling Marci's chasing/fleeing ability.
* Shadow Realm prevents Marci from bursting Willow down since she relies on physical attacks and unit target spells. With Aghanim's Scepter, Willow can hit Marci while Marci can't hit Willow.
* Bedlam and 
Eul's Scepter of Divinity allows Willow to manfight if Marci initiates with Rebound.
* Terrorize and Cursed Crown combo can waste Marci's ultimate for almost half of its duration.
Dark Willow
* 
Windrun does not protect Windranger from Cursed Crown's stun or Dark Willow's magical nukes.
* 
Focus Fire cannot target Dark Willow in Shadow Realm and will be interrupted if targeted earlier, wasting the ultimate.
Additional:
* Windrun does not protect Windranger from Cursed Crown stun or Dark Willow's magical nukes.
* Focus Fire cannot target Dark Willow in Shadow Realm and will be interrupted if targeted earlier, wasting the ultimate.
Dark Willow
* Terrorize forces Monkey King out of Wukong's Command.
Dark Willow
* Dark Willow's burst damage and stun prevents Troll Warlord from approaching her until he has Black King Bar.
* Troll Warlord's lack of burst damage makes it hard for him to kill Dark Willow before she slips into Shadow Realm.
Dark Willow
* Terrorize forces Faceless Void out of 
Chronosphere.
Medusa
* Mana Shield can tank most of the damage from Reaper's Scythe; with sufficient mana, the kill threshold drops significantly.
* Necrophos has a movement speed equal to Medusa, and is easy to chase down with a slowing item in Medusa's inventory.
Medusa
* 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
Medusa
* Medusa's Split Shot can make quick work of Enigma's Eidolons and take advantage of their considerable bounty.
* Medusa can also kill Eidolons with her Mystic Snake that can also greatly damage Enigma and drain some of his mana.
* If Medusa activates Stone Gaze at the start of a fight, it can make initiating and landing an effective Black Hole exceedingly difficult, because Stone Gaze can cancel Enigma's Black Hole even through spell immunity, which can discourage Enigma from even trying to initiate with Black Hole.
Additional:
* 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. Stone Gaze can cancel Enigma's Black Hole even through spell immunity, which can discourage Enigma from initiating with Black Hole.
Medusa
* Mana Shield makes Medusa very hard to take down in Duels.
* Stone Gaze stops Legion Commander from Dueling altogether, regardless of who she targets.
Medusa
* Split Shot can destroy Tombstone Zombies and Tombstone itself while still damaging heroes.
Medusa
* Visage's familiars are easy targets to Split Shot.
* Mana Shield will resist Soul Assumption instances without effort.
Medusa
* Heroes with a lot of burst damage, especially those who rely on casting spells: Lina, Zeus.
Medusa
* Heroes with Linken's Sphere as core item: 
Weaver, 
Morphling, Medusa.
Medusa
* Any hero who can counter-initiate in anticipation without getting caught in Reverse Polarity: Sven, 
Omniknight, Enigma, Luna, Naga Siren, Mars, Jakiro, Venomancer, Elder Titan, 
Faceless Void, 
Rubick, 
Keeper of the Light, 
Pugna, 
Invoker, Spectre, Alchemist, Treant Protector, Lina, Oracle, Zeus, 
Shadow Shaman, 
Phoenix, Razor, 
Huskar, Batrider, 
Kunkka, Tidehunter, Wraith King, Sand King, Medusa, Dawnbreaker.
Medusa
* Heroes with a lot of burst damage, especially those who rely on casting spells: Lina, Zeus.
Medusa
* Heroes that are hard to gank: Axe, Death Prophet, 
Phantom Lancer, Slark, 
Centaur Warrunner, Bristleback, Medusa, Mars.
Medusa
* 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.
Medusa
* Medusa's Split Shot and Mystic Snake combined with Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.
Additional:
* Medusa's Split Shot and Mystic Snake combined with Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.
Dark Willow
* Heroes with high burst damage and Black King Bar can take down Dark Willow quickly: Phantom Assassin, Sven, Wraith King
Medusa
* Stone Gaze allows Medusa to easily kite and kill Sven.
* Mana Shield negates much of Sven's burst damage.
Additional:
* Mana Shield makes it very hard for Sven to burst her within Storm Hammer's stun duration.
* Stone Gaze makes it very difficult for Sven to fight Medusa at any stage of the game.
* Mystic Snake can slow Sven down enough for allies to capitalize on his commitment in a fight.
Medusa
* 
Bulwark can make each of Medusa's attacks target him instead, reducing Medusa's contribution on team fights.
* 
Spear of Mars stuns Medusa and also pushes her away from teamfights, taking advantage of Medusa's low mobility.
* Arena Of Blood blocks Medusa's attacks from outside the arena.
Medusa
* Medusa's Stone Gaze forces Mars to choose between getting petrified, or turning his vulnerable back on Medusa.
Dark Willow
* Heroes with high magical or pure damage will bypass Bulwark: 
Timbersaw, Dark Willow, Enigma, Invoker, Pugna, 
Skywrath Mage, 
Tinker, Zeus, Oracle.
Dark Willow
* Heroes with high burst damage and Black King Bar can take down Dark Willow quickly: Phantom Assassin, Sven, Wraith King
Medusa
* Heroes with disables that ignore spell immunity will render Phantom Assassin completely useless in teamfights throughout the game: Axe, Enigma, 
Vengeful Spirit, 
Doom, Bane, Beastmaster, Pudge, Medusa, 
Warlock.
Medusa
* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: Tidehunter, Bristleback, Slardar.
Medusa
* 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.
Dark Willow
* 
Rage protects and dispels all of Dark Willow's abilities.
Additional:
* Rage protects Lifestealer from all of Dark Willow's abilities.
Medusa
* Lifestealer's low mobility makes him easy to kite.
* Stone Gaze pierces Rage, wasting its cooldown and making Lifestealer unable to fight.
Medusa
* Silencer burns easily through her effective HP from
Mana Shield, by taking away her intelligence.
Arcane Curse punishes her repeatedly casting 
Mystic Snake to keep her mana pool high. He can force her to use 
Manta Style before he has cast 
Global Silence and 
Medusa usually does not want to build 
Black King Bar.
*
Dark Willow
*
Last Word and 
Arcane Curse have the range to hit Dark Willow beyond Bramble Maze.
Global Silence renders Dark Willow useless in teamfights.
*