Corrosion

Full effect

This Pokémon's moves and item ignore the usual immunity of Poison and Steel Pokémon when attempting to inflict poison.

In game description

The Pokémon can poison the target even if it's a Steel or Poison type.

Using Corrosion in Cobblemon

Abilities are passive and always active, so Corrosion costs you nothing to run. If it is marked hidden on a species above, expect it to be harder to obtain: servers differ in whether hidden abilities come from breeding, an Ability Patch, or events.

See the Pokedex for which abilities each species can have, and IVs, EVs and breeding for how to actually pass one down.