Corrosion is an alchemy formula. It is taught by an alchemist found in Ebon Keep Sewers. It can be considered a variant of Acid Rain, altough it acts differently.


Corrosion deals 9-21 pure damage to all enemies on-screen and then deals continuous damage to them for 75 seconds, inflicting 4-11 damage every 2 seconds. This makes it similar to Slow Burn. Slow Burn, Corrosion and Plague can stack with eachother but does not stack with itself. This damage is pure and is not reduced by any form of defense. The total damage it deals is about 300 on average, but can be close to 400 if the player is lucky.

Corrosion is of little use, the major problem being that its damage does not increase as it levels up, and the damage it does is minimal. However, it does have a niche use in that it is the only alchemy formula the player gets that affects all enemies on-screen, while other formulas can only target up to three enemies. This makes Corrosion useful when facing multiple weak enemies.

Due to the fact that the damage dealt of Corrosion is pure (not reduced by anything) and that it can stack with Slow Burn and Plague, it could be useful against certain enemies/bosses with high magic defense like Carltron's Robot, if the player still wishes to use alchemy against them. When all 3 are used, the DPS can reach as high as 24 or 1450/minute.

It is used by Aquagoth and Mungola. It can be removed with any form of status healing.


Corrosion requires 1 part Mushroom and 3 parts Water for each casting.