The adorable frog-alligator-platypus tetranodon is a mix of a kappa, a water dwelling yokai, and a sumo wrestler. It even eats cucumber-like slugs (on the monster hunter twitter), much like the kappa. :
SITO Artchive: 'Kappa in his Cucumber Plane' by Caitlin Lehman
KAPPA MAKI ROLL - Food - Sushi Zushi
Kappa and cucumber - Stock Illustration [54173339] - PIXTA
Roll Sushi with Cucumber Kappa Maki One Isolated on White Background with Clipping Path Stock Photo - Image of delicious, dish: 170261430
kappa
AO Kappa Cucumber Pickles | Japanese Food - Haiku Future