Amabie
Amabie is a legendary Japanese mermaid or merman with a bird beak-like mouth and three legs or tail-fins, who allegedly emerges from the sea, prophesies either an abundant harvest or an epidemic, and instructed people to make copies of its likeness to defend against illness.
Source: Wikipedia, Amabie. Text licensed CC BY-SA 4.0. Not endorsed by or affiliated with Wikipedia or the Wikimedia Foundation.