[Single-card discussion] Gorgonic Guardian

2 Level 3 Rock-Type 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; its ATK becomes 0, and if it does, its effects are negated. These effects last until the end of this turn. Once per turn: You can target 1 monster on the field with 0 ATK; destroy it.