Once during your turn (before you attack), you may search your deck for Castform, Rain Castform, or Sunny Castform and switch it with Snow-cloud Castform. (Any cards attached to Snow-cloud Castform, damage counters, Special Conditions, and effects on it are now on the new Pokémon.) Shuffle Snow-cloud Castform back into your deck. You can't use more than 1 Temperamental Weather Poké-Power each turn.
Flip a coin. If heads, the Defending Pokémon is now Paralyzed. If tails, the Defending Pokémon is now Asleep.