* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

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

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Viper can bully Alchemist out of mid lane quite easily, forcing him to either retreat into jungle, or stay harassed in lane, and get very few last hits. Vipers break also completely disables Greevil's greed which prevents Alchemist to earn his amazing amounts of money.

* Since Windranger is bad against magical damage, heroes with continuous magical damage or magical nukes can blast her: Zeus, Tinker, Leshrac, Viper, Skywrath Mage, Lion, Lina, Venomancer.

* Heroes with plenty of summons, such as Broodmother or Nature's Prophet can have their minions soak up most of your Paralyzing Cask.

* 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.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* 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.

* Viper Strike breaks Sniper's passives.
* Corrosive Skin allows Viper to deal more damage to Sniper than Sniper deals to him when laning, especially by briefly stepping into Shrapnel.
* Nethertoxin together with Poison Attack can slow Sniper and tears through his low health and mobility.

* Sniper is completely helpless against Broodmother's abilities, and can be seriously damaged by Spiderlings in lane, especially when Shrapnel is on cooldown.

* Viper's poison abilities can slow Bounty Hunter's movement speed and allows to chase him with True Sight items.
* Nethertoxin can break Jinada, and the silence from level 25 prevents Bounty Hunter from using all of his spells.

* Bounty Hunter's single-targeted arsenal of abilities make him an easy target for Broodmother and her Spiderlings.
* Broodmother often buys Orchid Malevolence and it's upgrade Bloodthorn, which allows her to stop Bounty Hunter from escaping with Shadow Walk.
Additional:
* Like with Bane, Bounty Hunter's single-targeted arsenal of abilities make him an easy target for Broodmother and her Spiderlings.
* Broodmother often buys Orchid Malevolence and it's upgrade Bloodthorn, which allows her to stop Bounty Hunter from escaping with Shadow Walk.
* Spinner's Snare from Aghanim's Scepter allows Broodmother to create invisible lines on her webs from Spin Web that will root Bounty Hunter, deal damage over time to him and reveal him if he unwittingly steps on them, disrupting Bounty Hunter's ganking attempts with Shadow Walk while also alerting Broodmother on his attempts to ambush her and her allies.

* Hand of God has a long cooldown, so damage over time spells can be hazardous for Chen, forcing him to use it prematurely: Jakiro, Venomancer, Viper, Dazzle, Phoenix.

* Chen has no area-of-effect spells to deal with Broodmother's spiderlings and must rely on his creeps to take care of them.
* Spawn Spiderlings can kill Chen's creeps and spawn spiderlings in their place.
* Spin Web allows Broodmother to disrupt Chen's jungling.
* Silken Bola will cause Chen and his creeps's attack to miss more often while also making them more vulnerable to magical damage, especially if Broodmother picks 400 AoE Silken Bola talent.
* Broodmother is a natural Bloodthorn wielder, which will allow her to prevent Chen from trying to save himself with Hand of God while also making him more vulnerable to damage, and when combined with Insatiable Hunger, it will spell a quick and certain death for Chen. Bloodthorn's passive ability will also reduce any spell damage Chen tries to inflict with his creeps.
* Spinner's Snare from Aghanim's Scepter allows Broodmother to create invisible lines on her webs from Spin Web that will root Chen and his creeps, deal damage over time to them and reveal them if they unwittingly steps on them, disrupting Chen's jungling even more while also alerting Broodmother on their attempts to ambush her and her allies.
Additional:
* Chen has no area-of-effect spells to deal with Broodmother's spiderlings and must rely on his creeps to take care of them.
* Spawn Spiderlings can kill Chen's creeps and spawn spiderlings in their place.
* Spin Web allows Broodmother to disrupt Chen's jungling.
* Silken Bola will cause Chen and his creeps's attack to miss more often while also making them more vulnerable to magical damage, especially if Broodmother picks 400 AoE Silken Bola talent.
* Broodmother is a natural Bloodthorn wielder, which will allow her to prevent Chen from trying to save himself with Hand of God while also making him more vulnerable to damage, and when combined with Insatiable Hunger, it will spell a quick and certain death for Chen. Bloodthorn's passive ability will also reduce any spell damage Chen tries to inflict with his creeps.
* Spinner's Snare from Aghanim's Scepter allows Broodmother to create invisible lines on her webs from Spin Web that will root Chen and his creeps, deal damage over time to them and reveal them if they unwittingly steps on them, disrupting Chen's jungling even more while also alerting Broodmother on their attempts to ambush her and her allies.

* Corrosive Skin will protect Viper from Techies' magical damage.
* Even though Reactive Tazer will disarm Viper if he attacks Techies with Poison Attack, he does lots of damage with his other abilities that can still kill Techies.

* Heroes with summons like Broodmother, Enigma, Nature's Prophet; or illusions, like Naga Siren, Terrorblade are effective at keeping the choke points and rune spawns safe from Proximity Mines.

* Nethertoxin prevents the buildup of Jingu Mastery stacks.
* Viper's poison magical damage-over-time stops Monkey King from using Tree Dance. It also ignores the extra armor bestowed by Wukong's Command.
Additional:
* Viper STrike prevents the buildup of Jingu Mastery stacks.
* Monkey King's high base movement speed is of little worth against the array of slows Viper possesses.
* All of Viper's magical damage over time stops Monkey King from using Tree Dance. It also ignores the extra armor bestowed by Wukong's Command.

* Heroes with blind of some sort can be a bad choice for Monkey King to go on: Broodmother, Riki, Keeper of the Light.

* Heroes with break can disable Untouchable for a while: Doom and Shadow Demon (via Aghanim's Scepter), Viper, Shadow Shaman with Hex Breaks talent.

* Enchantress's lack of area-of-effect abilities allows Broodmother to swarm her with Spiderlings.
* Spawn Spiderlings can kill enchanted creeps and create Spiderlings in their place.
* However, bear in mind that Untouchable makes it harder for Broodmother to actually hit Enchantress, even if Broodmother is spell immune. And Broodmother's only way to counter this is either by buying Silver Edge, buying items that deal high magical damage like Dagon, or by buying items that give high attack speed like Moon Shard.
Additional:
* Enchantress can be easily overwhelmed with Broodmother's spiderlings from Spawn Spiderlings and Enchantress can only control one of them with Enchant and she has no good waveclear (Spawn Spiderlings can also kill creeps controlled with Enchant).
* However, Untouchable's attack speed reduction can make it difficult for Broodmother to kill Enchantress even with any form of spell immunity.

* The damage over time from Viper's Poison Attack and Viper Strike rapidly wear down Refraction charges, allowing Templar Assassin to be damaged. Additionally, Corrosive Skin causes her attacks to apply damage overtime on her as well.
* Nethertoxin is a big threat to Templar Assassin. Her initially low range making it very hard to deal against Nethertoxin in the laning phase. At any stage of the game, a Nethertoxin can always force her to undo her Meld.
Additional:
* All of Viper's abilities quickly burn through Refraction charges.
* Templar Assassin's short range, aside from Psi Blades' spill damage, makes her vulnerable to Poison Attack harassment.
* Templar Assassin usually buys health and armor items for damage. Outside of Black King Bar, Viper will almost always be able to kill her when Refraction is down.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* Viper's Nethertoxin disables Cloak and Dagger, negating Riki's invisibility and much of his damage. It also makes him more vulnerable to magic damage, which does not go well with Riki's low health pool. With the talent applied, he can't even blink to safety or hide with Tricks of the Trade.
* Corrosive Skin makes it hard for Riki to chase Viper and attack him due to the attack speed slow.
* Viper Strike stays on Riki even after he goes invisible.
* Poison Attack makes it risky for Riki to get last hits and can make the laning phase difficult for him.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* Heroes with damage-increasing passive abilities, such as Viper and Riki, will usually kill Silencer in a short time before he even has time to set up his abilities.

* Broodmother relies less on abilities and more on right-clicks.
* Spiderlings can overwhelm Silencer, who has mediocre armor and no escape tool.

* Corrosive Skin minimizes the damage from Impale and Mind Flare, and anything else Nyx Assassin tries to throw at Viper.
* Nyx Assassin cannot survive several poison damage-over-time output from Poison Attack, Nethertoxin, Corrosive Skin and Viper Strike, not even while he has Spiked Carapace active. And to make things worse, Nyx Assassin is not a common Silver Edge wielder to counter this problem at all.
Additional:
* Corrosive Skin minimizes the damage from Impale and Mind Flare, and anything else Nyx Assassin tries to throw at Viper.
* Nyx Assassin cannot survive several poison damage-over-time output from Poison Attack, Nethertoxin, Corrosive Skin and Viper Strike, not even while he has Spiked Carapace active. And to make things worse, Nyx Assassin is not a common Silver Edge wielder to counter this problem at all.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* Heroes that can apply early pressure before Phantom Assassin has farm are massive threats: Axe, Viper, Meepo, Jakiro, Pugna, Slark, Venomancer etc.

* Phantom Assassin's single target abilities make her very helpless against swarms of Spiderlings without Battle Fury.
* Because Phantom Assassin is always reliant on critical strikes, Broodmother will usually have enough time to use Spin Web to save herself.
* Silken Bola can cripple Phantom Assassin greatly due to her being 100% reliant on physical attacks.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Phantom Assassin, deal damage over time to Phantom Assassin and reveal Phantom Assassin if she unwittingly steps on them, disrupting her attempts to initiate or escape with with Phantom Strike while also alerting Broodmother on her attempts to ambush her and her allies.
Additional:
* Phantom Assassin's single target abilities make her very helpless against swarms of Spiderlings without Battle Fury.
* Because Phantom Assassin is always reliant on critical strikes, Broodmother will usually have enough time to use Spin Web to save herself.
* Silken Bola can cripple Phantom Assassin greatly due to her being 100% reliant on physical attacks.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Phantom Assassin, deal damage over time to Phantom Assassin and reveal Phantom Assassin if she unwittingly steps on them, disrupting her attempts to initiate or escape with with Phantom Strike while also alerting Broodmother on her attempts to ambush her and her allies.

* Viper Strike can disable Gravekeeper's Cloak, Visage's primary defense mechanism.
* Viper can ignore Grave Chill's attack speed slow with his magic damage output.
Additional:
* Since Visage is a slow hero, Viper can easily kite him with Poison Attack and Viper Strike while successfully chipping away at Gravekeeper's Cloak.
* Nethertoxin removes all layers of Gravekeeper's Cloak, leaving Visage exposed.
* Corrosive Skin makes Viper highly resistant to Soul Assumption.

* Heroes with very little to no area-of-effect abilities will struggle greatly against Broodmother: Sniper, Phantom Assassin, Nyx Assassin, Bane, Visage, Bounty Hunter.

* Viper Strike is a strong and breaks Fury Swipes, undispellable slow, making it much easier to kite Ursa for everyone.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Spiderlings melt away Living Armor almost instantly.
* The vision from Eyes In The Forest may prove dangerous for Broodmother, however.

* Any hero who can survive Magnus's initiations and manfight him: Huskar, Faceless Void, Weaver, Abaddon, Troll Warlord, Alchemist, Dragon Knight, Night Stalker, Viper.

Additional:
* Most of Magnus's abilities except Empower will trigger damage through Corrosive Skin.
* Poison Attack and Viper Strike can slow Magnus during Skewer, as well as putting his Blink Dagger on cooldown, preventing him from initiating or re-initiating.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* Broodmother's Incapacitating Bite can make Nuerta's miss her attacks from Gunslinger more often until she buys items that require Javelin.
* Broodmother can still use Spawn Spiderlings to hurt Muerta while she has Pierce The Veil active as it deals magical damage and has a low cooldown.
* Broodmother can buy Revenant's Brooch to attack Muerta even through Pierce The Veil with Insatiable Hunger.
* Spin Web's movement speed gain for Broodmother makes it difficult for her to hit Broodmother with Dead Shot and keep her trapped in The Calling.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare which allows her to create up to 5 invisible web lines on her webs from Spin Web that can deal magical damage over time to Muerta, root her and reveal her if she unwittingly steps on them, foiling both, her escaping and ganking attempts while allowing Broodmother to alert her allies about her attempting to ambush them.

* The slow applied from Corrosive Skin offsets the movement speed bonus granted by Scorched Earth and the tick-based damage from Infernal Blade and Doom will continually slow Doom down. This allows Viper, much like Sniper, to 'kite' Doom and keep him at a safe distance between the two. Additionally, Corrosive Skin applies an attack-speed slow which is fairly crippling to a hero such as Doom that, naturally, has a high base attack-time, poor agility gain and builds little attack-speed items.
* Since Doom does not disable auto-cast abilities, Viper's Poison Attack will continue to work. Doom may find it hard to close the distance between himself and Viper, and thusly difficult to effectively lockdown and continually deal damage through his abilities.

* Corrosive Skin means Viper can often outlast Venomancer in a battle of attrition.
* Venomancer has no mobility without items, which makes him vulnerable to constant slows.

* Though Mirana can clear waves of Broodmother's spiderlings with Starstorm, Broodmother will often stick with her spiderlings from Spawn Spiderlings, which in combination with the huge speed provided by Spin Web can make it hard for Mirana to hit her with Sacred Arrow.
* Broodmother commonly buys Orchid Malevolence and it's upgrade Bloodthorn, which allows her to prevent Mirana from escaping with both, Leap and Moonlight Shadow and from fighting back with Starstorm.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Mirana, deal damage over time to Mirana and reveal Mirana if she or any of her allies unwittingly step on them while affected by Moonlight Shadow, disrupting her attempts to initiate with Moonlight Shadow and Sacred Arrow, and prevent her to use Leap while also alerting Broodmother on her attempts to ambush her and her allies.
Additional:
* Though Mirana can clear waves of Broodmother's spiderlings with Starstorm, Broodmother will often stick with her spiderlings from Spawn Spiderlings, which in combination with the huge speed provided by Spin Web can make it hard for Mirana to hit her with Sacred Arrow.
* Broodmother commonly buys Orchid Malevolence and it's upgrade Bloodthorn, which allows her to prevent Mirana from escaping with both, Leap and Moonlight Shadow and from fighting back with Starstorm.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Mirana, deal damage over time to Mirana and reveal Mirana if she or any of her allies unwittingly step on them while affected by Moonlight Shadow, disrupting her attempts to initiate with Moonlight Shadow and Sacred Arrow, prevent her to use Leap while also alerting Broodmother on her attempts to ambush her and her allies.

* Corrosive Skin makes Viper receive less damage from Invoker's spells
* Viper can harass Invoker with his Poison Attack in the early game.
* Viper Strike and Poison Attack can kill Invoker easily if Ghost Walk is on cooldown.

* Broodmother can kill Invoker easily in the early game with her Spawn Spiderlings and her spiderlings.
* Broodmother is both an Orchid Malevolence and a Nullifier carrier. As she can farm it early, she can kill Invoker easily.

* Corrosive Skin severely reduces Zeus's damage output throughout the game.
* During the laning stage, Viper can abuse Zeus' reliance on spells by hugging the creep wave. Zeus will take constant damage over time from Corrosive Skin unless he drives Viper from the lane or returns to farming in his absence.
* Prior to buying Blink Dagger or Force Staff, Zeus is fragile and possesses low mobility. Any of Viper's numerous slows can set up an easy kill.
Additional:
* Corrosive Skin counters Zeus in lane by canceling the effects of Clarity as Zeus relies on Arc Lightning to farm and secure last hits.
* Corrosive Skin also increases Viper's magic resistance to shrug off Zeus's magical nukes.
* Nethertoxin breaks Static Field.
* Due to Zeus' poor mobility, Viper Strike will cripple Zeus and will allow Viper and his teammates to land a lot of attacks.

* Nethertoxin disable passives, negating Spectre's damage and survivability by removing both Dispersion and Desolate.
* Due to Haunt and Radiance's burn, Spectre is heavily susceptible to being persistently slowed and damaged by Corrosive Skin without even directly attacking Viper.
* Poison Attack and Viper Strike further slow Spectre's movement speed to a crawl, while his improved magic resistance means he can easily shrug off Radiance's burn.
Additional:
* Viper Strike can disable Desolate and Dispersion, leaving Spectre with far less damage output and damage mitigation in engagements.
* Spectre is one of the weakest heroes at early levels. Viper can stifle her farm with early fights before Spectre purchases any major items.

* His Poison Attack is very useful against Huskar, since he tends to stay at low health.
* Nethertoxin disables passive skills like Berserker's Blood.
* It is dangerous for Huskar to jump on Viper because Corrosive Skin and Viper Strike with the slowdown of movement and attack speed which usually will be deadly for Huskar.
Additional:
* Viper Strike can disable Berserker's Blood, which Huskar relies upon for attack speed and healing.
* The damage from Burning Spear and Life Break is largely absorbed by Corrosive Skin. It also will return some damage, making it risky to use Burning Spears in the laning stage.
* Because Huskar wants to be on low health for Berserker's Blood, he is particularly vulnerable to Poison Attack.

* Viper's skill set makes him an effective early game ganker against Anti-Mage before he is sufficiently farmed.
* Viper's Corrosive Skin and low mana pool causes him to take little damage from Mana Void.
* Nethertoxin disables Mana Break and Counterspell, weakening both his offense and defense.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* Drow Ranger's lack of mobility and area-of-effect abilities makes her easy prey for Broodmother and her Spiderlings.

* Nethertoxin disables Dawnbreaker's Luminosity. Since she's a melee hero, she needs to close gap to attack and Nethertoxin will be bad for her since she cannot heal.
* Viper Strike and Poison Attack will severely slow her down and combined with Nethertoxin, it will be her death sentence (unless her Celestial Hammer or Solar Guardian are off cooldown). Besides that, chasing her down will be easy due to the slow.

* Viper's Poison Attack and Viper Strike that can slow Razor, and is one of the few heroes that can keep him immobile.
* Altogether, Viper's skills reduce Razor's attack speed, heavily reducing the benefit of the damage drain from Static Link.
Additional:
* Storm Surge is counteracted by Viper Strike, leaving Razor without his extra movement speed.
* Static Link's damage drain doesn't bother Viper a lot as most of his early to mid game damage is magical.

* Corrosive Skin gives Viper additional resistance to Phoenix's magical damage, and since they deal damage over time, Phoenix would be constantly afflicted by his passive's own debuff, making him not an ideal target for Phoenix's harassment. Phoenix's abilities also constantly drain its own health away, becoming more vulnerable to Poison Attack.

* Corrosive Skin minimizes the damage Viper takes from all of Disruptor's skills.

* Viper Strike breaks Multicast.
* Corrosive Skin minimizes the damage from Ignite and Fireblast.

* Nethertoxin disables Vengeance Aura.
* Vengeful Spirit has no mobility spells aside from Nether Swap, which Viper can take advantage of with his slows.
* Viper can easily bully Vengeful Spirit out of a lane with Poison Attack.
Additional:
* Viper Strike can disable the attack damage bonus from Vengeance Aura and the components of Nether Swap.
* Both Magic Missile and Wave of Terror are counteracted by Corrosive Skin, making Vengeful Spirit's fighting harder against Viper.

* 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.

* Because Poison Attack has almost no cooldown, Aphotic Shield is ineffective as a hard dispel.
* Viper Strike can prevent Borrowed Time from activating passively and block Curse of Avernus.
Additional:
* Because Poison Attack has almost no cooldown, Aphotic Shield is ineffective as a hard dispel.
* Viper Strike can prevent Borrowed Time from activating passively and block Curse of Avernus.

* 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.

* Heroes who can easily harass Crystal Maiden out of lane in the early game (Clinkz, Viper) can prevent Crystal Maiden from being able to level effectively, and can ultimately slow down her level 6, 12, and 18 to a point where enemy carries already have items to address her ultimate.

* 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).

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Heroes that can slow Charge of Darkness by a huge amount: Venomancer, Viper, Dazzle, Arc Warden, Lion, Huskar, Shadow Shaman, Visage, Undying, Jakiro.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* 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.

* Poison Attack makes it hard for Void Spirit to lane against him.
* Corrosive Skin reduces the magical damage from Void Spirit's spells.

* With Aghanim's Scepter, Broodmother will gain access to Spinner's Snare, which will allow her to create invisible lines on her webs from Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, Ursa, Nature's Prophet, Enigma, Void Spirit, Magnus etc.

* 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.

* 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.

Additional:
* Chain Frost can bounce to the Spiderlings that Broodmother spawns.

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Broodmother can easily clear Wraith King's skeletons with Spawn Spiderlings and summon spiderlings in their place.
* With Diffusal Blade, Broodmother can prevent Wraith King from reincarnating unless Wraith King has his Aghanim's Shard.

* Heroes with illusions and summons can manfight Night Stalker: Terrorblade, Beastmaster, Broodmother.

* 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.

* Oracle cannot easily deal with swarms of units, making him weak against heroes like Phantom Lancer or Broodmother.

* Heroes who can harass Omniknight out of lane will keep him weak in the mid game: Viper, Venomancer, Clinkz.

* Nethertoxin breaks the damage block from Bulwark.
* Poison Attack and Viper Strike's slows make it difficult for Mars to contribute to fights due to his low mobility.
Additional:
* Viper Strike can disable Bulwark entirely, making Mars far less tanky. Using Nethertoxin inside Arena of Blood may discourage enemies from following up with Mars's initiation.
* Rod of Atos is currently common on Viper and keeps Mars in position long enough to be killed.
* However, Viper is not very tanky earlier in the game, so positioning against Mars is important for Viper since a well-timed Spear of Mars can be the end of Viper.

* Sprout cannot protect Nature's Prophet if Broodmother puts down a web.
* Nature's Prophet's low mobility means he is defenseless against Silken Bola.
* Spiderlings can absorb much of the damage from Wrath of Nature.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Nature's Prophet, deal damage over time to Nature's Prophet and reveal Nature's Prophet if he unwittingly steps on them, disrupting his attempts to perform surprise attacks on Broodmother's allies with Silver Edge and also prevent him from using Silver Edge to esacape, while also alerting Broodmother on his attempts to ambush her and her allies.
Additional:
* Broodmother can destroy Nature's Prophet's Treants with Spawn Spiderlings and summon spiderlings in their place.
* Broodmother loves buying Orchid Malevolence, which can prevent Nature's Prophet from escaping with Sprout and Teleportation.

* Viper wins on the central line of Puck, because he has a huge damage from the Poison Attack ability, which Puck is not able to constantly avoid using Phase Shift, which will give Viper an advantage in the possible damage inflicted on each other
* Puck takes more damage than it does due to the passive Corrosive Skin ability of the Viper, which makes it unprofitable for the Puck to fight against the Viper at an early stage of the game, when the Puck has a very small pool of health.
Additional:
* Viper wins on the central line of Puck, because he has a huge damage from the Poison Attack ability, which Puck is not able to constantly avoid using Phase Shift, which will give Viper an advantage in the possible damage inflicted on each other
* Puck takes more damage than it does due to the passive Corrosive Skin ability of the Viper, which makes it unprofitable for the Puck to fight against the Viper at an early stage of the game, when the Puck has a very small pool of health

* Broodmother can kill Enigma's Eidolons with Spawn Spiderlings, and spawn her spiderlings in their place. But remember that Enigma can do the same to Broodmother's spiderlings with Demonic Conversion and Midnight Pulse.
* Without the protection from Black King Bar, Broodmother can cancel Enigma's Black Hole with Bloodthorn and make him more vulnerable to damage. Broodmother can also buy Abyssal Blade to cancel Enigma's Black Hole even through Black King Bar.
* Silken Bola causes Enigma's attacks to miss a lot and renders him more vulnerable to magical damage. And if Broodmother takes 400 AoE Silken Bola, then she will be able to use to cause Enigma's Eidolons to miss their attacks as well. In addition, Enigma does not like to buy items to provide him true strike such as Bloodthorn, Monkey King Bar, Witch Blade and it's upgrade Revenant's Brooch.
* If Broodmother is lucky enough to survive being trapped in Black Hole, she will be able to recover her lost health with Insatiable Hunger.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Enigma, deal damage over time to Enigma and reveal Enigma if he unwittingly steps on them, disrupting his attempts to initiate with Black Hole, prevent him from using Blink Dagger, while also alerting Broodmother on his attempts to ambush her and her allies.
Additional:
* Broodmother can kill Enigma's Eidolons with Spawn Spiderlings, and spawn her spiderlings in their place. And Enigma can't use Demonic Summoning to instantly kill spiderlings at once.
* Without the protection from Black King Bar, Broodmother can cancel Enigma's Black Hole with Bloodthorn and make him more vulnerable to damage. Broodmother can also buy Abyssal Blade to cancel Enigma's Black Hole even through Black King Bar.
* Silken Bola causes Enigma's attacks to miss a lot and renders him more vulnerable to magical damage. And if Broodmother takes 400 AoE Silken Bola, then she will be able to use to cause Enigma's Eidolons to miss their attacks as well. In addition, Enigma does not like to buy items to provide him true strike such as Bloodthorn, Monkey King Bar, Witch Blade and it's upgrade Revenant's Brooch.
* If Broodmother is lucky enough to survive being trapped in Black Hole, she will be able to recover her lost health with Insatiable Hunger.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Enigma, deal damage over time to Enigma and reveal Enigma if he unwittingly steps on them, disrupting his attempts to initiate with Black Hole, prevent him from using Blink Dagger, while also alerting Broodmother on his attempts to ambush her and her allies.

* None of Arc Warden's abilities are very effective against Broodmother and her spiderlings.
* A good Broodmother looks to end the match early while Arc Warden, a very item reliant hero, thrives in longer matches.
* Arc Warden has no innate disables to stop Broodmother from lifestealing with Insatiable Hunger and shredding through his relatively lower armor.

* Heroes with Attack speed decreasing skills: Jakiro, Viper Lich

* Illusion-based and multi-unit heroes can take advantage of Chaos Knight's lack of area damage: Naga Siren, Phantom Lancer, Broodmother

* Nethertoxin disables Bristleback's passive.
* Viper Strike and Poison Attack slow down Bristleback's movement speed, making him unable to get out from Nethertoxin.
Additional:
* Viper Strike can disable Bristleback and prevents Warpath from building stacks. Besides losing his defensive passive, Bristleback also loses his ability to build up damage over lengthy battles.
* Viper can perpetually kite Bristleback with Poison Attack and Viper Strike.

* In the early game, a Dragon Knight without Black King Bar is basically defenseless against Viper.
* Viper can harass Dragon Knight at any time with his Poison Attack and Nethertoxin.
* Corrosive Skin reduces damage from Dragon Fire and inflicts damage to him.
* Viper Strike disables Dragon Blood, negating his main survivability.
* Viper Strike and Poison Attack can severely slow him down even with his Elder Dragon Form.
Additional:
* Dragon Knight is easily harassed by Poison Attack after the laning stage ends.
* Corrosive Skin protects Viper from Breathe Fire and returns damage.
* Viper Strike can disable Dragon Blood, Dragon's Knight main source of armor and health regeneration.
* Between Poison Attack and Viper Strike, Viper can keep Dragon Knight permanently slowed even in Elder Dragon Form.

* Tiny has low movement speed and attack speed, making him vulnerable to Viper's slows.
* Corrosive Skin provides magic resistance to lower Tiny's magic burst damage.

* Viper does large amounts of magic damage over time, meaning that if a Necrophos uses Ghost Shroud, Viper's abilities will greatly reduce Necrophos survivability, and may actually kill him.
* By the same token, Viper can use his Viper Strike on Necrophos if he attempts to heal himself with Ghost Shroud, and depending on any other effects Necrophos may have from him, (IE:Poison Attack,Corrosive Skin), Viper can often kill Necrophos while he is in his Ghost Shroud.
* Viper's Corrosive Skin helps him take reduced damage from all of Necrophos spells that deal magical damage, which is his only source of damage.
Additional:
* Viper Strike prevents Heartstopper Aura from dealing damage or healing Necrophos.
* Viper's magic damage is amplified whenever Ghost Shroud is used.
* Corrosive Skin makes Viper tankier against Death Pulse and Reaper's Scythe.

* Viper Strike prevents Timbersaw from gaining stacks on Reactive Armor.

* Nethertoxin both Necromastery and Presence of the Dark Lord, reducing his damage massively.
* Corrosive Skin gives Viper bonus Magic Resistance against Shadowraze and Requiem of Souls.
* Viper can easily take advantage of Shadow Fiend's lack of escape and mobility spells with Viper Strike breaks and Poison Attack. Poison Attack also serves as a great way to harass Shadow Fiend.

* Viper STrike cancels out Kraken Shell and stops the hard dispel from passively activating, preventing Tidehunter from functioning as a frontline tank.
* Anchor Smash is mostly irrelevant against a ranged hero like Viper.
* Tidehunter relies on the threat of Ravage, which has an obscenely long cooldown. Viper can exploit the downtime with his short cooldowns.

* Corrosive Skin minimizes the damage Viper takes from all of Ancient Apparition's abilities.
* Ancient Apparition's slow movement speed, squishy nature, and lack of escape abilities can easily be taken advantage of through Poison Attack and Viper Strike.

* Poison Attack and Viper Strike allowing to kite and slow Earthshaker significally, putting Blink Dagger on cooldown and preventing him from initiating or re-initiating.
* Nethertoxin breaks Aftershock. The silence from Level 25 talent also prevents Earthshaker from initiating or re-initiating.
Additional:
* Being a melee hero, Earthshaker's movement is liable to suppression by Poison Attack and Viper Strike.
* Earthshaker's kit, with the exception of Enchant Totem, deals magic damage. Corrosive Skin effectively blunts his killing potential with a standard Blink combo among other things.
* Viper Strike can disable Aftershock, which removes the stun and bonus damage from Enchant Totem and Echo Slam.

* Viper Strike prevents the lifesteal from Ransack.
* Meepo and his clones have a lack of magic resistance, so they're vulnerable to Poison Attack & Viper Strike directed onto one clone.

* Viper Strike prevents buildup of Fiery Soul stacks.
* Corrosive Skin provides magic resistance against Lina's spells. However, Lina can counter this with Silver Edge, a common item on Lina.
* Poison Attack and Viper Strike can burn away Lina's small health pool.

* Insatiable Hunger's attack damage amplification can reduce the effectiveness of Enfeeble, and the Enfeeble will not weaken the magical damage output from Silken Bola, Spawn Spiderlings and Spinner's Snare from Aghanim's Scepter, though it will still reduce their cast range.
* Bane's single-targeted arsenal of abilities make him an easy target for Broodmother and her Spiderlings.
* Broodmother often buys Orchid Malevolence and it's upgrade Bloodthorn, which allows her to cancel Fiend's Grip, and completely shut Bane down.
Additional:
* Insatiable Hunger's attack damage amplification can reduce the effectiveness of Enfeeble, and the Enfeeble will not weaken the magical damage output from Silken Bola, Spawn Spiderlings and Spinner's Snare from Aghanim's Scepter, though it will still reduce their cast range.
* Bane's single-targeted arsenal of abilities make him an easy target for Broodmother and her Spiderlings.
* Broodmother often buys Orchid Malevolence and it's upgrade Bloodthorn, which allows her to cancel Fiend's Grip, and completely shut Bane down.

* 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.

* Poison Attack and Viper Strike slows Axe significantly, and puts his Blink Dagger on cooldown, preventing him from initiating. Viper Strike can also break from Counter Helix.
Additional:
* Viper Strike prevents Counter Helix from triggering, which significantly lowers Axe's damage output in the early to mid game.
* Viper's various slows and damage over time prevents Axe from initiating as well as putting his Blink Dagger on cooldown.