Ampharosデンリュウ

AbilityElectromagnetic Wall

As long as this Pokémon is your Active Pokémon, whenever your opponent attaches an Energy from his or her hand to 1 of his or her Pokémon, put 3 damage counters on that Pokémon.

Does 20 damage to 1 of your opponent's Benched Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)