Ōkubi

Ōkubi (大首) (おおくび) (the giant head) is a Japanese yōkai. Its image is mostly a huge female head and has the characteristics of a married woman's teeth painted black. Their true identities are said to be human vengeful spirits and obsessions turned into yōkai. Some say that Ōkubi is not a Japanese monster in folklore but was created to satirize monks who broke their precepts.