The Under Guppy is the ruler of the Under Guppy Realm, and is played by Nonny. His first and only appearance was in The Puppy And The Ring. When wearing his hoodie of invisibility, he has the ability to turn invisible.
The Under Guppy looks exactly like Nonny, except he wears a green hoodie.
The Under Guppy has an army of bats that he can call forth by simply raising his hands.