From Dota 2 Wiki
- Fortune's End applies a basic dispel which can be used to purge Corrosive Haze, or even Slardar's own Guardian Sprint.
- False Promise is able to purge off Slardar's Corrosive Haze and Slithereen Crush stun/slow from any allies Oracle chooses to cast it on.
- Fate's Edict can also be cast on Slardar to prevent him from proccing his Bash of the Deep.
- Abaddon can cast Aphotic Shield on any of his allies to immediately purge Corrosive Haze and/or the stun and the slow components of Slithereen Crush.
- All of Slardar's debuffs are also removed if Abaddon's Borrowed Time triggers.
- Phantom Lancer has a low cooldown basic dispel from Doppelganger, making it hard to keep Corrosive Haze on him. Can also build Manta Style and Diffusal Blade.
- Slardar does not do well against illusions and has a low mana pool, making Phantom Lancer with Diffusal Blade annoying, to say the least.
- Slardar does not do well against multiple targets, as his only way to damage multiple targets being Slithereen Crush.
- Medusa cares less than other heroes about armor reduction, since Mana Shield blocks 60% of all damage without taking armor/magic resistance into consideration. This makes 60% of your Corrosive Haze ineffective until Medusa's mana is drained.
- Terrorblade starts out with and gains a lot of armor from his agility growth. His illusions also make it difficult for Slardar to focus down the real Terrorblade.
- Tidehunter purges off Haze and stun if bursting him is attempted often leading to Slardar's team being baited into Ravage. Also Anchor Smash reduces Slardar's already low damage, so Tidehunter stays tanky even against Slardar.
- Slardar relies on Blink Dagger initiation, so any illusion-based hero (especially with Radiance) can scout you out and/or cancel your blink.
- Illusion heroes like Phantom Lancer, Luna, Arc Warden.
- Given that Slardar's damage output is entirely physical, there is almost nothing he can do when enemies activate Ghost Scepter.
- Shiva's Guard provides armor which helps against Slardar, while the passive attack slow also prevents him from attacking as often.
- Radiance, Butterfly, Heaven's Halberd, Solar Crest can reduce the value of your Corrosive Haze with constant misses and can be hard for Slardar to itemize against, requiring Black King Bar, Monkey King Bar or both. Same goes true for his allies that want to take advantage of the armor reduction.
- Diffusal Blade and Necronomicon can be a pain to deal with until Slardar gets a Black King Bar.
- Invisible and fragile. With Diffusal Blade no longer capable of dispelling Corrosive Haze Riki lacks a good option against Slardar: Riki will not win most straight-up fights even without being stunned, and doesn't have nearly enough health or armor to survive being focused on with Corrosive Haze. Slardar's Guardian Sprint is usually enough to chase effectively, and even Riki's ultimate Tricks of the Trade will rarely deal enough damage to matter much against Slardar. If you find yourself in this untenable position it is recommended to use Smoke Screen aggressively or have a support interfere with Slardar.
- Clinkz is fragile, and relies on Skeleton Walk to escape from battles quickly. Corrosive Haze grants True Sight on Clinkz, making his invisibility useless, and makes him even more squishy for the time being. Do not underestimate Clinkz however, as late game, Clinkz can tear down most heroes with Strafe and Searing Arrows along with Desolator which is commonly built by Clinkz.
- Bounty Hunter's Shadow Walk is rendered useless with Corrosive Haze and makes Bounty Hunter an easy target for Slardar and his team.
- Weaver relies on Shukuchi to escape and kite enemy heroes. Slardar's Corrosive Haze reveals Weaver, who is already a very frail target.
- Weaver usually builds Linken's Sphere, Corrosive Haze can be used to "pop" the spell block of Linken's Sphere, letting Allied heroes use their abilities on Weaver.
- Shadow Fiend, a normal Shadow Blade builder often relies on its invisibility to escape fights. Corrosive Haze reveals Shadow Fiend and also weakens his already low armor.
- Alchemist has a low starting armor and a low agi growth, which translates to a low armor growth . And since it is very uncommon for Alchemist to get straight to Assault Cuirass, or Shiva's Guard, Corrosive Haze makes him too vulnerable to physical damage, even with the hp regeneration of Chemical Rage
- With armor items like Solar Crest or Assault Cuirass combined with Bash of the Deep, Slardar can easily tank the Duel, If not dueled himself, he can drop Legion Commander's armor during duel and/or buff his teammate and save them, leaving her only the choice of dueling supports which can also be saved with fast Blink into Slithereen Crush.
- Invoker's Ghost Walk can be countered, however, Invoker could also use abilities like Tornado or Ice Wall to escape by other means.
- Nyx Assassin's Vendetta can be revealed easily by Corrosive Haze
- Slark's Pounce can be interrupted with Slithereen Crush, and Shadow Dance's invisibility is useless when Slardar uses Corrosive Haze.
- Crystal Maiden's already low armor and easily interruptible ultimate, Freezing Field can make Slardar her worst nightmare. Crystal Maiden also often builds Glimmer Cape which is revealed by Corrosive Haze.
- Mirana's ultimate Moonlight Shadow makes her and all her allies invisible for a duration. Corrosive Haze reveals invisibility, making Moonlight Shadow useless.
- Linken's Sphere because Corrosive Haze has shorter cooldown than Spellblock 8 seconds (13-5).
- Slardar's Bash of the Deep is Physical so Black King Bar won't prevent the Bash.
- Broodmother as Corrosive Haze reveals her while in Spin Web.
Works well with...Bounty Hunter
- Corrosive Haze significantly increases the damage from Jinada.
- Bounty Hunter commonly builds Desolator as well, further amplifying physical damage done to the enemy.
- Wave of Terror and Corrosive Haze used in tandem will drastically reduce the enemy's armor and amplifying physical damage.
- Shadow Fiend's passive Presence of the Dark Lord reduces armor to enemies around him, along with Corrosive Haze Shadow Fiend, mainly being a basic attack hero, will easily be able to tear down foes.
- Combined with Alchemist's further armor reduction with Acid Spray and given the fact that his Unstable Concoction does physical damage, it can allow Alchemist to deal huge amounts of damage.
- Templar Assassin's Pure Damage basic attacks from Psi Blades is amplified greatly with the use of Corrosive Haze.
- Templar Assassin also commonly builds Desolator, which also reduces enemy armor.
- Templar Assassin's second ability, Meld reduces enemy armor as well.
- Elder Titan's Natural Order leaves enemies near him at 0 armor. Corrosive Haze further decreases the enemies' armor, leaving them with a negative armor value, making them take amplified physical damage.
- Phantom Assassin's Ultimate Coup de Grace and Stifling Dagger does more damage with Corrosive Haze being cast on the target.
- Anti-Mage's Mana Break deals physical damage, in conjunction with Slardar's armor reduction, all of Anti-Mage's basic attacks will deal even more damage.
- Generally any hero who is reliant on physical damage/basic attack damage works well with Slardar because of Corrosive Haze.
- Generally any hero who benefits from the vision granted by Corrosive Haze, even if they don't deal physical damage, like Tinker