A kappa —also known as kawatarō , komahiki , with a boss called kawatora or suiko —is a reptiloid kami with similarities to yōkai found in traditional Japanese folklore. Kappa can become harmful when they are not respected as gods. They are typically depicted as green, human-like beings with webbed hands and feet and turtle-like carapaces on their backs. A depression on its head, called its "dish" (sara), retains water, and if this is damaged or its liquid is lost, the kappa is severely weakened.

In Slavic mythology, vodyanoy is a water spirit. In Czech and Slovak fairy tales, it is called vodník, and it is considered to be the equivalent creature as the Wassermann or nix of German fairy tales. In Ukrainian fairy tales, it is called “водяник“ (vodyanyk).