Legendary mermaids have an upper body of a human with long flowing hair, and a lower body of a fish. They live in ocean habitats and have supernatural abilities, sometimes protecting marine life and sometimes harming humans. In one popular myth they enchant sailors with their beautiful songs, causing them to crash their ships on the rocks. In some cautionary tales they can make wishes come true in return for something valuable, but the deals often have a catch. In Japanese culture they are omens of bad luck, causing earthquakes, tsunamis, and shipwrecks.