A catastrophic event That only happens when all mice and rodents on earth disappear leaving cats nothing else to eat but humans. If you do not "let the dogs out" cats will devour your flesh, organs and poop. After devouring some of your body you are infected and turn into a cat/human hybrid. The Alpha cats eat the weaker cat/humans and shit them out creating an endless food supply.
dude 1 :wow that cat is eating that human it must be hungry
Dude 2: oh no a catpocalypse :(