could green dude be modeled after a Japanese kappa. Maybe he is an armless kappa. They both have a beak and the white line on the head might be a plate. :
Kyōgen mask of a kappa, 2019 by Kitazawa Hideta :: | Art Gallery of NSW
Japanese Kappa: The Yokai That Loves Butts
Kappa | InuYasha | Fandom
Kappa”: The Terror of Japan's Rivers | Nippon.com
Kappa - Character (10279) - AniDB
Japan Society - Kappa - Water Goblin A creature with frog-like skin, a beak, a tortoise shell on the back and a plate on its head that is filled with water. Despite