Game-breaking bug in Ability Draft with Viper Strike ability

[green-sam]

Description

Viper Strike's Aghs ability Nose Dive can be exploited to produce an extremely impactful bug. With the right combination of inputs, the hero with this spell is able to cast spells into the ground, which remain there for the rest of the match. It means the enemy team's creeps can never reach the base as they are killed by permanent spells.

It works with spells that are AOE and produced from the body of the caster including lina's dragon slave, gush aghs, crypt swarm. Impale and Avalanche produce a stun effect, all permanently on the ground.

Hesitant to explain exactly how to do this bug in case anyone sees it here and ruins games with it. The basic idea is that if you cast nose dive in a certain way, it causes the hero to be facing the ground instead of the horizon. If somone from Valve responds I can explain how to do it fully to them.

Example Match ID (and possibly Timestamp)

7728077723

[Bloppppppp]

This one needs to be fixed asap. People are catching on to it & this bug makes the game literally unplayable.

[DragNH3art]

This bug is not only limited to AD but also can be replicated in normal games with Rubick or Morphling replicating Viper's Nosedive effect. The abusing hero only needs to perform the Nosedive bug once and will persist in a "faceplanted" position during which the exploit can be abused.

Hypothesis: Certain inputs on Nosedive will rotate the caster but does not correctly return to an upright position. While "faceplanted" compatible spells casted using same method will attempt to cast in the direction the hero model is facing. Since the hero is facing directly downwards the spell will attempt to propagate into the ground, however the ground blocks the propagation of the spell, resulting in the spell never reaching its max distance and therefore never expiring. Therefore this spell only works with forwards propagating spells that do not have a fixed duration and expire upon reaching max distance. Spells that can be casted at variable distances (such as Beastmaster Wild Axes) are not affected. Spells that have a fixed duration (such as Elder Titan Earth Splitter) will expire normally despite having an abnormal casting pattern.

This "faceplant" position can be reset by using Nosedive normally or casting other spells that affect the rotation of the hero, and while face planted any spell that makes the hero "jump" or move forward will cease to move the hero as the hero's movement is blocked by the ground. Note that any given unit can only be affected by each instance of the spell once, so this bug is of limited effect to heroes, but since creep waves spawn new units every wave a small amount of exploited casts can permanently disable enemy creep waves.

A list of spells that permanently linger on the ground:

• Satyr Tormentor Shockwave (stolen via Doom)
• Dragon Knight Breathe Fire
• Pudge Meat Hook (it seems only one Hook can exist for any given caster - the abusing hero can leave a stationary Meat Hook but recasting Meat Hook removes the previous cast; affected targets are pulled towards the point of initial cast)
• Gush (with Aghanim's Scepter)
• Clinkz Burning Army (Skeletons will all spawn around the caster instead of in a line)
• Shadow Fiend Shadowraze (all variants of Shadowraze will now affect enemies directly around the caster instead of the appropriate distance)
• Spectre Spectral Dagger
• Weaver The Swarm
• Ancient Apparition Ice Blast (Tracer will stay in place permanently until Ice Blast is released; Blast radius seems to always be minimum)
• Death Prophet Crypt Swarm
• Jakiro Dual Breath
• Keeper of the Light Illuminate
• Lina Dragon Slave
• Lion Earth Spike (a unit affected by Earth Spike will become immune to any Earth Spikes casted prior to it being affected)
• Shadow Demon Shadow Poison
• Clockwork Hookshot (refer to Meat Hook; also it does not seem to be consistently affected by this exploit, after 20 attempts it only bugged out once)
• Invoker Tornado
• Mirana Sacred Arrow (the Aghanim's Scepter Starfall effect seems to follow same logic as Earth Spike)
• Nyx Assassin Impale (refer to Earth Spike)
• Pangolier Swashbuckle (caster will be permanently immobile until death)
• Pangolier Aghanim's Scepter Shield Crash (leaves near-invisible permanent Swashbuckles that allow for global attacks)
• Snapfire Scatterblast
• Timbersaw Timber Chain (refer to Meat Hook, except with trees)
• Vengeful Spirit Wave of Terror
• Venomancer Venomous Gale
• Windranger Powershot

A list of mobility spells that cease to work properly (moves in place unless stated otherwise):

• Force Staff Force
• Force Boots Force
• Hurricane Pike Hurricane Thrust ally effect
• Earth Spirit Rolling Boulder (renders caster invulnerable and immobile indefinitely until an enemy hero walks into the caster)
• Monkey King Boundless Strike Shard Alt Cast
• Slark Pounce (Pounce will now latch enemies around the caster including enemies behind the caster)
• Sniper Shard Concussive Grenade (only if casted with the exploit method, leaves a permanent grenade visual projectile if performed this way)
• Ursa Earthshock
• Crystal Maiden Shard Crystal Clone
• Enchantress Sproink
• Puck Illusory Orb (orb stays in place)
• Mirana Leap base effect (also fixes rotation for future casts)
• Pangolier Shield Crash
• Snapfire Firesnap Cookie (Shard Mortimer's Kisses Globs on Firesnap Cookie effect seems to never connect to the ground)

Spells that theoretically should be affected but don't:

• Kunkka Shard Tidal Wave (most likely due to the origin point of Tidal Wave being offset from the centre of the hero)
• Mars Spear of Mars
• Clinkz Shard Burning Barrage
• Drow Ranger Multishot
• Troll Warlord Whirling Axes (Ranged)
• Grimstroke Stroke of Fate (refer to Tidal Wave)
• Queen of Pain Sonic Wave
• Magnus Shockwave
• Zeus Heavenly Jump (correctly jumps forward)

This list is based on testing by myself in Demo Mode via Rubick. I have made this list as exhaustive as possible but there is still a small likelihood I missed some spells that interact with this bug.

Proposal: Create a special case prevents model rotation for this specific input. Also, make spells that do not have a max duration have a maximum lifetime (maybe 60s) after which they expire to prevent similar interactions in the future.

[Dagsss]

Experienced the same thing in my AD game, with Doom with Viper Strike and Earth Spike.