As legend has it, in the 1800s a mythical yokai appeared off the coast of Kumamoto, Japan. The Amabie, as it was called, was described as a mermaid-like creature with long hair, a beak and 3 legs. It made several predictions related to bountiful harvests and, before disappearing back into the sea, left the locals with some advice in case of an epidemic.
(Cited from spoon-tamago http://www.spoon-tamago.com/2020/03/13/amabie-japanese-epidemic-yokai/)