Gumbald

Gumbald is Princess Bubblegum's great-uncle. Although he has not yet appeared in an episode, Princess Bubblegum mentioned him in "Susan Strong," claiming that he had cut down an entire field of taffy trees in a single night; the reason for which is unknown. Finn and Jake had to pull out all the tree stumps that he left behind.

Trivia

 * Some people get his name confused with "Gumball."
 * So far, he is the only known relative of Princess Bubblegum that hasn't been "created" by her.