Gengar LC 11

Once during your turn (before your attack), you may move 1 damage counter from 1 of your opponent's Pokémon to another (even if it would Knock Out the other Pokémon). This power can't be used if Gengar is Asleep, Confused, or Paralyzed.

If your opponent has any Benched Pokémon, choose 1 of them and this attack does 10 damage to it. (Don't apply Weakness and Resistance for Benched Pokémon.)