Muzurhythm the String Djinn

[ Fiend / Xyz / Effect ] 2 Level 3 monsters When a "Djinn" Xyz Monster you control is attacking an opponent's monster, during the Damage Step: You can detach 1 Xyz Material from this card; the attacking monster's ATK is doubled until the End Phase. You can only use this effect of "Muzurhythm the String Djinn" once per turn. ATK/ 1500 DEF/ 1000