During damage calculation (in either player's turn), if a "Warrior" Synchro Monster you control battles an opponent's monster: You can send this card from your hand to the Graveyard; your battling monster's ATK becomes double its current ATK during that damage calculation only. You can banish this card from your Graveyard, then target 1 "Synchron" monster in your Graveyard; add it to your hand. You can only use each effect of "Rush Warrior" once per turn.