Gooey
Lowers attacking Pokémon's Speed by one stage on contact.
In game description
Contact with the Pokémon lowers the attacker's Speed stat.
Pokemon with Gooey
Using Gooey in Cobblemon
Abilities are passive and always active, so Gooey 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.