Dark Honest (VASM-EN047) - Valiant Smashers 1st Edition

Once per turn, during your Main Phase: You can return this face-up card to the hand. During the Damage Step, when your DARK monster battles an opponent's monster (Quick Effect): You can send this card from your hand to the GY; that opponent's monster loses ATK equal to its own ATK, until the end of this turn.