Kuchisake-Onna

One of the scariest japanese urban legends is about the slit-mouthed woman kuchisake-onna. She appears at night and asks: "Am I beatiful?" If you say that she isn´t, she´ll kill you. If you tell her she is, she pulls away her surgical mask and you can see her mouth that is slit from one ear to the other. Then she cuts your mouth just like hers.