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. :
Kappa Yokai Monster Fleece Hat Ready to Ship Halloween - Etsy
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