Gumbald is Princess Bubblegum and Neddy's great-uncle. Although he has not yet appeared in an episode, Princess Bubblegum mentions him in "Susan Strong," claiming that he had cut down an entire field of taffy trees in a single night for some unknown reason. Finn and Jake were supposed to pull out all the tree stumps that he left behind but only pulled out one before encountering a metallic hatch that led them to Susan Strong.
Additionally, in the episode "Hot Diggity Doom," it is revealed that Gumbald built the log cabin that Princess Bubblegum and Peppermint Butler had to reside in after the King of Ooo took leadership of the Candy Kingdom.
- He is one of the known relatives of Princess Bubblegum that has not been "created" by her.
- Neddy is then shown in "Bonnie and Neddy" to be one as well.