Banana Man is responsible for building a rocket ship which is similar to the one in Jake's croak dream. He traveled to the Tree Fort to borrow some sugar, but Finn misinterpreted his presence as a threat and never answered the door. Walking back to his geodesic dome home, he is seen dancing to an exercise tape. He performs the routine again at the end of the episode.
Finn tries two times to shoot him with his crossbow. The flaming arrow then flies over the house, and they find a half-built spaceship. Jake then uses the arrow to light some dynamite in the rocket. Banana Man comes out and says that there is not enough for the rocket to work. The dynamite blows a hole in the ground, and all three fall in. They survive the fall but end up in a pool of water. Jake believes that he and Banana Man will run into one another later in life. Banana Man's rocket ship is destroyed, and it lies in an underground cave full of water, which resembles Jake's croak dream in space.
Banana Man returns in "We Fixed a Truck," where he helps Finn, Jake and BMO rebuild their truck Hot Daniel. He expresses gratitude toward Finn and Jake for letting him hang out with them, and they in turn talk him up to a female Banana Guard on whom he has a crush. He winds up helping save the Candy Kingdom from a Lizard replica of Princess Bubblegum with his peel, though he winds up being arrested by his crush for public indecency. Princess Bubblegum informs BMO this is only a minor offense, though.
His imprisonment apparently did not last long, as he was shown listening to Jake's broadcast from his futuristic geodesic dome home in "Jake the Brick." It is possible that he escaped with the other prisoners in "Apple Wedding," when the cells were opened.
In Banana Man's appearance in "The Comet," it is shown that he successfully finished building his rocket, as he was seen travelling in space in it. At some point while he was flying it, he encountered Jake, who was likely running out of air in his spacesuit, and saved him, bringing him aboard his ship. This event was possibly a fulfillment of Jake's croak dream, despite Jake not dying, due to the similar circumstances they were under. Banana Man then safely lands back on Earth with Finn, Jake, and Orgalorg, who had reverted back to Gunter due to Earth's gravity, in Lake Butterscotch.
Banana Man returns again in "President Porpoise is Missing." In the episode, he helps Finn and Jake investigate President Porpoise's disappearance with his sub (and apparently hides in their Tree Fort from time to time, along with most of Finn and Jake's other friends and associates). He is the only one who actually tries looking for President Porpoise, but finds himself distracted by an instant connection with an undersea representative named Sybil. As the episode ends, he and Sybil watch the sunset from the ocean's surface while Finn and Jake are left in the submarine wondering where he is and running out of air. Presumably, he came back and got them eventually.
Banana Man's body is shaped to look like the top slice of a banana, and he wears a peel that serves as a shirt and hood. A thin banana stem adorns the top of his hood. His exposed face, arms, and legs are a paler shade of yellow than his peel. He wears dark brown shoes. He sometimes wears a glass bowl on his head, like an astronaut's helmet. His round eyes have whites, unlike many other characters, and his pupils are round, large, and black.
Personality and character traits
Banana Man is interested in outer space. He wanted to take his rocket into space, but Finn and Jake probably ruined Banana Man's chances of doing that in "The New Frontier" when they crashed his rocket. Banana Man also likes to workout while watching instructional fitness videos on his TV.
Banana Man is one of the few characters in Ooo who appears to have an understanding of pre-Mushroom War science and technology, both in his building a rocket and in helping Finn and Jake fix a derelict truck.
As devoted to construction as he seems, Banana Man is lonely and wishes for someone to "share his life with." This is demonstrated when he tells BMO "It sure would be nice to find somebody."
There's not enough boom boom stickhole sticks in the stickhole! GAHHH!
I just wanted to borrow some sugar!
Yeah, baby! Work it!