Symbiosis
Passes the bearer's held item to an ally when the ally uses up its item.
In game description
The Pokémon passes its held item to an ally that has used up an item.
Pokemon with Symbiosis
Using Symbiosis in Cobblemon
Abilities are passive and always active, so Symbiosis 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.