It is said that the Japanese giant salamander is the inspiration behind the mythological creature known as the kappa, an imp or a demon that live in the rivers of Japan. :
Giant Japanese Salamander | River Monsters Wiki | Fandom
Ancient Aliens: The Legendary Japanese Kappa (S8, E7) | History - YouTube
Nishinakasu Kappa in Nishinakasu/Haruyoshi, Fukuoka - SAVOR JAPAN