If Thundurus is on your Bench, this attack does 20 damage to each of your opponent's Benched Pokémon. (Don't apply Weakness and Resistance for Benched Pokémon.)
Put a Pokémon from your hand face down in front of you. Your opponent guesses the type of that Pokémon, and then you reveal it. If your opponent guessed right, they draw 4 cards. If they guessed wrong, you draw 4 cards. Return the Pokémon to your hand.