Amanjiru resembles a cow Yokai in a big cup of hot chocolate and three marshmallows. And has whipped cream on its head.
People who get soaked in Amanjiru's broth become unambitious and lose their drive.
In the Anime
Amanjiru debuted in EP141, where Nate discovered him making his parents become shiftless. Nate summons Jibanyan to fight Amanjiru, but before Jibanyan can attack, Amanjiru takes off. After chasing Amanjiru through town, Nate, Jibanyan and Whisper corner Amanjiru at Triangle Park, which prompts Amanjiru to throw some of his broth at Nate. This causes Nate to become so unambitious, he not only gives up chasing Amanjiru, but gives up his title as main character, making Jerry the star of the show (with Tomnyan and Verygoodsir replacing Jibanyan and Whisper).