Gumbald is a gum person who was created by Princess Bubblegum to be her and Neddy's Uncle. Princess Bubblegum first 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 first physically seen in "The Thin Yellow Line" being thrown in prison by Princess Bubblegum. The episode does not reveal who he is.
His first present appearance is in Three Buckets, where he collects Fern's remains and asks him if he'd like an Uncle. He is not truly named until the episode "Bonnibel Bubblegum." (in The Wild Hunt he is simply called Uncle G.) It is shown that he is possibly as skilled a scientist as Princess Bubblegum in "The Wild Hunt," as he created the Grumbo, a large, hot fudge shooting Banana Sloth that had been attacking the Banana Guards.
Not much is known about Gumbald in the beginning of the series, as Bubblegum scarcely talks about him. In "Susan Strong," it is mentioned that he cut down an entire field of plum trees in a single night for the Candy Kingdom.
He is mentioned again in "Hot Diggity Doom" when Princess Bubblegum tells Peppermint Butler that Gumbald had built the cabin they were repairing during Bubblegum's exile.
In the "Thin Yellow Line," Gumbald is seen during the Banana Guard's story about the Princess, detailing how dangerous and mysterious the guards see her. In the story, Gumbald is seen thrown in jail, cowering. It is not revealed he is Gumbald until later on.
In "Three Buckets," Gumbald makes his first appearance in the present, as well as his first speaking role. He wears a cape with a large "G" logo on it. After Finn accidentally shreds Fern with his prosthetic arm, Gumbald is seen putting Fern's remains in a bucket, and he asks the pile of grass if he needed an Uncle. He is not named in this episode, but his first line hints at his true identity.
n "Bonnibel Bubblegum," it is revealed that he was created by a lonely Bonnibel Bubblegum. She wanted have more family than just Neddy. Due to this, she created Uncle Gumbald, along with Aunt Lolly and Cousin Chicle. They lived peacefully as Gumbald and the rest of the family built a candy town and planted taffy trees. However, Gumbald cut down the taffy trees to build a log cabin. He revealed to his niece that he had plans to build a candy city. Bonnie however, did not like that idea so she used a butterscotch bomb to make Lake Butterscotch where Gumbald intended to build the city. This infuriated Gumbald but, he had a backup plan. He sent Bonnibel away after creating her a boyfriend, Mr. Cream Puff. While she was away, Gumbald along with Bonnibel's other intelligent relative-creations, Lolly, and Chicle were discussing a plan to overthrow her and build a candy city. He formulated a "happy juice" that would make Bubblegum more docile and simple-minded like Mr. Cream Puff. Gumbald tricked Lolly and Chicle into eating happy juice-induced cupcakes turning them into Manfried and Crunchy, forgetting their previous selves. Bonnibel caught this. Gumbald voiced that Bonnie tried to keep him in line but stated he was her equal as she denounced him as evil. He tried to make Bonnie have the juice, while threatening her brother Neddy but with the help of a peashooter, she shot the beaker with the happy juice while Gumbald was holding it. The happy-juice splashed onto Gumbald's face and turned him into the Punch Bowl and forgetting his previous self. At the end, Bubblegum becomes aware he is back since she recognized the cup BMO had got from a scientist.
In "Seventeen", it is revealed the Punch Bowl was reverted back into his previous-self, Gumbald due to the events of "Skyhooks II", in which Lumpy Space Princess' anti-elemental lumps reverted everything into its "true shape." Gumbald and his family disguised themselves as a horse for a warrior revealed to be Fern. Gumbald stops Fern from killing Finn and revealed himself along with his family to Bubblegum who was shocked to see him. He revealed how they changed back to normal and tried to turn Bubblegum into a candy person for keeping them trapped for centuries but Marceline interfered. Scared by her, he decided to retreat along with his allies though promised to be back.
As Punch Bowl, he appears as a large glass bowl of fruit punch with large white eye with purple pupils.
As Gumbald he appears as humanoid gum person with a piece of hair on the top of his head. He also has a mustache and a beard on the bottom of his face. He is seen wearing both a royal clothing, but also appears wearing a tan tunic and purple cape.
As Punch Bowl, he was a simple minded candy person who enjoyed having fun.
In his true form as Gumbald, he is shown to be very intelligent rivaling that of his "niece". When he was first created, Gumbald was very kindhearted and even thanking Bonnibel for giving a "Greatest Uncle" mug. However, when he made plans to create his own kingdom, he got angry at Bonnibel's attempts to sabotage them even throwing destroying the mug she gave him. He slowly made plans to overthrow Bonnibel, to that end he created a boyfriend to distract her and turned her other created relatives Lolly and Chicle against her. While in his planning, he insulted Bonnibel in a slideshow with one of his reasons for disliking her leadership was because she was a bad niece, despite her being kind to him. Gumbald also showed he thinks about himself as he used his "happy juice" on his partners and showed no remorse for it. He took great pride in himself as he stated he was Bonnibel's equal before he was turned into a candy person.
After turning back, he has made plans to exact revenge on Bonnibel as well as those she has befriended as he created a new body for Fern and had him attack Finn though prevented him from killing Finn. When he revealed himself, he tried to turn Bonnibel into a candy person and would have succeeded if Marceline had not interfered. He also shows a sense of survival, as he didn't try to attack Bonnibel again since in his words "the vampire girl is legitimately scary", which caused him to retreat.
- "The Enchiridion!" (as Punch Bowl, unofficial debut)
- "Holly Jolly Secrets Part II" (as Punch Bowl)
- "Bad Timing" (as Punch Bowl)
- "Jake the Brick" (as Punch Bowl)
- "Hoots" (as Punch Bowl, dream)
- "Hot Diggity Doom" (as Punch Bowl)
- "The Dark Cloud" (as Punch Bowl)
- "The Thin Yellow Line" (cameo, flashback)
- "High Strangeness" (as Punch Bowl, cameo)
- "Skyhooks II" (as Punch Bowl)
- "Three Buckets" (physical debut; not named yet)
- "The Wild Hunt" (not named)