Attach Gold Berry to 1 of your Pokémon that doesn't have a Pokémon Tool attached to it.
At any time between turns, if there are at least 4 damage counters on the Pokémon Gold Berry is attached to, you may remove 4 of them and discard Gold Berry. At the start of each turn, if there are at least 4 damage counters on the Pokémon Gold Berry is attached to, remove 4 of them and discard Gold Berry.
