Futakuchi-onna is a yokai from Japanese mythology. It literally translates to "two-mouthed woman". She has one normal mouth, and a second one in the back of the head. Futakuchi-onna doesn't eat much herself, but her hair moves like tentacles and feeds the second mouth, which is insatiably hungry.
EDIT (after the voting): Polished some things I wasn't completely satisfied with when I entered it to the weekly. It also looks pretty cool in waifu2x now.