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. :
Kaiyodo Kappa Museum – Shimanto-chō, Japan - Atlas Obscura
Japanese Kappa: The Yokai That Loves Butts
Easy Kappa Maki Recipe (Japanese Cucumber Sushi Roll) - Chef JA Cooks
Kappa and Cucumber, by Hotei Hokuga. Japan, early 19th century | V&A Images
Kappa Maki (Cucumber Sushi Rolls) | Sudachi
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Unknown: Kappa with Cucumber - Robyn Buntin of Honolulu - Ukiyo-e Search
Kappa - The Kappapedia: cucumbers
Cute Japanese Folk Monster Kappa Holding Stock Vector (Royalty Free) 1660616308 | Shutterstock