Honest (SDHS-EN014) [Structure Deck: HERO Strike]

During your Main Phase: You can return this face-up card from the field to the hand. During either player's Damage Step, when a 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 of this turn.