Ferrothorn (TEU #103)

This attack does 20 damage times the amount of Metal Energy attached to this Pokémon to 1 of your opponent's Benched Pokémon. You can't do more than 100 damage to a Benched Pokémon in this way. (Don't apply Weakness and Resistance for Benched Pokémon.)

During your opponent's next turn, this Pokémon takes 20 less damage from attacks (after applying Weakness and Resistance).