Balloon Berry (EX Deoxys 84/107)

As long as Balloon Berry is attached to a Pokémon, that Pokémon's Retreat Cost is 0. When this Pokémon retreats, discard Balloon Berry.

Card rule

Attach Balloon Berry to 1 of your Pokémon that doesn't already have a Pokémon Tool attached to it. If that Pokémon is Knocked Out, discard this card.