Once during your turn (before your attack), you may search your deck for any Castform and switch it with Castform Snow-cloud Form. (Any cards attached to Castform Snow-cloud Form, damage counters, Special Conditions, and effects on it are now on the new Pokémon.) If you do, put Castform Snow-cloud Form on top of your deck. Shuffle your deck afterward. You can't use more than 1 Temperament Poké-Power each turn.
This attack does 10 damage to each of your opponent's Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)