When an attack is declared involving a "Battlin' Boxer" monster you control and an opponent's monster, if you control another "Battlin' Boxer" monster: Negate the attack, and if you do, send your battling monster to the Graveyard, then 1 "Battlin' Boxer" monster you control gains ATK equal to your opponent's battling monster's original ATK, and if it does, proceed to damage calculation between that monster and your opponent's battling monster. Then, take damage equal to the ATK gained by this effect.