Turn it upside down so the cat looks sad then he gets emo and cut himself, but since a cat cant handle a knife he cuts his aorta and bleeds to death.
FUUUUUUUUUUUUUUUUUUUUUUUUUUUUU Maybe with um, a hammer, he is a rock after all. Oh and BTW ponies can't be killed by haters, we still just love and tolerate all parasprites.