Ningyo are much like a Japanese version of the mythological mermaid of the West. They are depicted as part-human and part-fish. Sometimes they have human-like arms and torso, but are often portrayed as a giant fish with only a human face. They are apparently extremely tasty creatures and will provide longevity in life when eaten, but they often bring ill-luck and disaster.
The tale of Yaobikuni tells of a fisherman who caught a strange-looking fish. He invited his friends over to feast. When one of the guests noticed that the animal had a human-looking face, he secretly warned the others not to partake in the meal. So as not to offend their host, the companions all wrapped up the flesh and hid it away. All of the men discarded the meat on the way home, except for one who was drunk. Forgetting what he was told, he gave the leftover meal to his hungry daughter. Unknowingly, she ate the Ningyo and lived one for 800 years, traveling the landscape and marrying over and over again. It wasn’t until she returned home that she was finally able to pass away.