Walrein

Once during your turn (before your attack), you may reveal the top card of your deck. If that card is a basic Energy card, attach it to 1 of your Pokémon. If not, put the card back on your deck. This power can't be used if Walrein is affected by a Special Condition.

Flip a coin. If heads, each Defending Pokémon can't attack during your opponent's next turn.