PHGN-EN005 Number C17: Storm Leviathan

Card text
3 Level 3 monsters
You can also Xyz Summon this card by using a "Number 17: Leviathan Dragon" you control as the Xyz Material. (Xyz Materials attached to that monster also become Xyz Materials on this card.)
Once per turn: you can detach 1 XYZ material from this card; this card gains 1000 ATK. If this card would be destroyed by an opponent's card effect: you can detach 2 XYZ materials from this card instead. This card cannot attack your opponent directly.