Corrosion

Corrosion allows the Pokemon to inflict poison and bad poison on Steel-type and Poison-type Pokemon, which are normally immune to being poisoned. This applies to moves like Poison Gas, Toxic, and Toxic Spikes, as well as the poisoning effects of items like Toxic Orb when used with Trick or Switcheroo.

The ability only bypasses the poison immunity of Steel and Poison types — it does not affect any other immunities or resistances. Poison-type moves still deal their normal type-based damage; Corrosion specifically enables the status condition to be applied where it normally could not.

Corrosion is found on Salandit, Salazzle, Glimmet, and Glimmora. It is particularly notable in competitive play for allowing Toxic to hit Pokemon like Ferrothorn, Heatran, and Toxapex that would otherwise be immune. Combined with Salazzle's access to Toxic, this ability removes a key defensive advantage that Steel-types typically enjoy.