 There, the woman's skull splits apart, forming lips, teeth and a tongue, creating an entirely functional second mouth.In Japanese mythology and folklore, the futakuchi-onna belongs to the same class of stories as the rokurokubi, kuchisake-onna and the yama-uba, women afflicted with a curse or supernatural disease that transforms them into yōkai.The supernatural nature of the women in these stories is usually concealed until the last minute, when the true self is revealed.