The Futakuchi-Onna is strange in the way that it is a yokai created from a living woman inflicted with a curse. A husband or relative may find that their food supply has been depleting rather quickly, indicating that they may be in the presence of a Futakuchi-Onna.
Whether a punishment for stinginess, the manifestation of her starved child, or something else entirely, the woman may appear to eat very little, but she is forced to satiate a terrible mouth on the back of her head that gnashes and whispers obscenities. Whenever the woman tries to eat, her hair will whip around like tentacles and steal it from her to feed the maw. If not satisfied, it will cause the woman horrible pain by screeching loudly. So she must provide the mouth with twice the amount of food that she requires herself.
Sound familiar? Lots of pop culture characters are based on this yokai—even a Pokémon!
The innocent chibi art style gives the drawing a bit of dissonance.