Flip 3 coins. If 1 of them is heads, put 4 damage counters on the Defending Pokémon. If 2 of them are heads, remove 1 damage counter from the Defending Pokémon. If all of them are heads, put 10 damage counters on the Defending Pokémon. If all of them are tails, remove all damage counters from the Defending Pokémon.