Choose 1 Basic Pokémon in any player's discard pile. Put it onto that player's Bench. Put a number of damage counters on that Pokémon equal to half its HP (rounded down to the nearest 10). (You can't put a Pokémon on a Bench that's full.)
Flip a number of coins equal to the number of damage counters on the Defending Pokémon. This attack does 20 damage times the number of heads.
