Confrérie du Poing de Feu - Rhino LTGY-FR028

If a "Fist of Fire" monster you control attacks or is attacked, during the damage calculation (on each player's turn), once per battle, you can send 1 "Fire Formation" Spell/Trap Card you control and 1 "Fist of Fire" monster from your hand to the Graveyard, during damage calculation only, your attacking/attacked monster gains ATK equal to the original ATK of the monster sent to the Graveyard.