Mika recently brought up the Japanese modern legend of Kuchisake-onna (口裂け女). For background, I turned to the English Wikipedia article on Kuchisake-onna which had the following to say about the figure (the description matches Mika’s memory):
According to the legend, children walking alone at night may encounter a woman wearing a surgical mask, which is not an unusual sight in Japan as people wear them to protect others from their colds or sickness.
The woman will stop the child and ask, “Am I pretty?” If the child answers no, the child is killed with a pair of scissors which the woman carries. If the child answers yes, the woman pulls away the mask, revealing that her mouth is slit from ear to ear, and asks “How about now?” If the child answers no, he/she will be cut in half. If the child answers yes, then she will slit his/her mouth like hers. It is impossible to run away from her, as she will simply reappear in front of the victim.
To help anyone who is not only frightened, but also confused, Mika and I made the following decision tree of possible conversations with Kuchisake-onna and their universally unfortunate outcomes.
Of course, we uploaded the SVG source for the diagram to Wikimedia Commons and used the diagram to illustrate the Wikipedia article.