a creature about half a metre tall with a shell like that of a tortoise on its back
a Japanese water spirit that pulls children into the water, drowning them
a legendary Japanese creature out of mythology
a mythical Japanese creature that has green scales, a turtle-like beak and shell, and small tufts of black hair on its head
an amphibious creature that often shows up in Japanese tales
A mythological river imp that preys on travelers. A kappa has fish scales, a turtle shell, a face like a bird or a monkey, and a dish-shaped depression on the top of its heads that holds a liquid that is the source of its superhuman strength.
(kahp-ah)—cucumber used in rolls
In this context, a 'kappa' is a water-demon of Japanese mythology. In the traditional Chinese tale, Gojyo's character is a water-demon. Kappa also means 'cucumber' in Japanese, hence the joke.
(KAHP-pah) A turtle-shelled creature that lives in rivers; kappa are known for their maliciousness.
Japanese folklore. However they are also considered to be a part of cryptozoology, due to apparent sightings. In Shintoism they are considered to be one of many suijin (literally "water-deity").
Kappa is also a number of Japanese sounding rockets, which were built starting from 1956.