Honest (SDBE-EN017) - Structure Deck: Saga of Blue-Eyes White Dragon Unlimited

During your Main Phase: You can return this card from the field to its owner's hand. During either player's Damage Step, when a face-up LIGHT monster you control battles: You can send this card from your hand to the Graveyard; that monster gains ATK equal to the ATK of the opponent's monster it is battling, until the End Phase.