Nure-onna

Nure-onna is a Japanese yōkai drawn in Edo-period picture scrolls and books as a woman with a snake's body. In a legend from Shimane she comes out of the sea holding a baby that turns to stone.

The Nihon Kokugo Daijiten, via Kotobank, defines nure-onna as a kind of monster, possibly of the same family as the iso-onago, iso-hime and umi-nyōbō, and cites the 1830 essay collection Kiyū Shōran. Japanese Wikipedia says Edo-period picture works such as Hyakkai Zukan and Gazu Hyakki Yagyō show her as a woman with a serpent's body, which suggests she was well known then. It adds that no story about the snake-bodied figure has been found in classical texts of that time.

Japanese Wikipedia says the folklorist Fujisawa Morihiko, writing in the early Shōwa era, gave a story set in the Edo period, but named no primary source for it.

English Wikipedia records a separate legend from the Iwami region of Shimane Prefecture. There a nure-onna serves the ushi-oni. She comes out of the sea, hands the baby she is holding to someone, and goes back into the water. The person tries to throw the baby and run, but it has become a heavy stone stuck fast, and the ushi-oni arrives and kills and eats that person.

The tourism association of Sakaiminato, on its Mizuki Shigeru Road yōkai page, gives its own description: her tail reaches three chō, about 327 metres, so anyone she spots is pulled back however fast they run.