2 Level 4 "Chronomaly" monsters
Once per turn, during either player's turn: You can detach 1 Xyz Material from this card, then target 1 face-up monster your opponent controls; change its ATK to 0 until the end of this turn. You can Tribute 1 "Chronomaly" monster, then target 1 monster your opponent controls, whose current ATK is different from its original ATK; destroy that target.