Giovanni's Gyarados 5

Flip 2 coins. If both of them are heads, this attack does 20 damage to each other Pokémon (even your own). Don't apply Weakness and Resistance for this attack. Damage:

Unless this attack Knocks Out the Defending Pokémon, choose 1 of your opponent's Benched Pokémon and switch it with the Defending Pokémon. Damage: 40