Iron Barbs

Damages attacking Pokémon for 1/8 their max HP on contact.

Full effect

Whenever a move makes contact with this Pokémon, the move's user takes 1/8 of its maximum HP in damage. This ability functions identically to Rough Skin.

In game description

Inflicts damage on the attacker upon contact with iron barbs.

Pokemon with Iron Barbs

Using Iron Barbs in Cobblemon

Abilities are passive and always active, so Iron Barbs 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.