Futakuchi Onna

In Japanese folklore, Futakuchi onna is a yokai who appears as a regular woman, however she has a second mouth hidden on the back of her head beneath her hair. This mouth is voraciously hungry and uses strands of hair as tentacles to gather food and stuff it into her extra mouth. 

Some people believe this yokai is actually a yama uba (mountain witch) disguising herself as a young woman. There are also suggestions that futakuchi onna are cursed women, resulting from not caring well enough for children, especially step children. Another possibility is that they are the result of frustrated women who have repressed their true feelings over many years and not spoken out.

Takehara Shunsensai, Ehon Hyaku Monogatari.
So if your food supplies start to decrease quickly, but you notice your female house member not eating, you may have a yokai problem on your hands. Good news though, other than eating you out of house and home, they are relatively benign, with no known fatalities reported.

Artist unknown