From The Pokemon Insurgence Wiki
Corrode is a damage-dealing Poison type move exclusive to Pokémon Insurgence.
Corrode deals damage and has no secondary effect. If used on Steel type Pokémon, this move ignores the type effectiveness of this move's type against Steel and treats it as being super effective against Steel types instead (even during Inverse Battles or if Corrode's type is changed). If Corrode's type is already super effective against Steel (due to being an Inverse Battle or if Corrode's type is changed), it will still only be 2× effective against Steel. The type effectiveness of Corrode's type against any other types the target has is determined normally.