Neither player can activate cards or effects in response to this card's activation. When a monster declares an attack: Destroy 2 Set cards you control, and if you do, negate that attack, then, if any Monster Cards were destroyed by this effect and sent to the GY, choose 1 and destroy as many monsters your opponent controls as possible with ATK less than or equal to that monster's DEF, then it becomes the End Phase. You can only activate 1 "Hidden Fangs of Revenge" per turn.