The Balloons make their first appearance in "Ricardio the Heart Guy." They fly up on screen in this episode when Princess Bubblegum says that she'll throw a party for Finn and Jake for rescuing her from Ice King once again. The screen says "PARTY TIME!" and the balloons fly up, transitioning to the next scene.
They appear again in "What is Life?" and they have more importance in the episode. In "What is Life?" it is mentioned that they are great pranksters. One of them said that he stole Finn's wallet; this seems impossible because the balloons have no arms. When Finn jumps to use them, they move out of the way, allowing Finn to plummet. A few of the balloons end up saving Finn, which implies it was a prank. The balloons apparently had a blood oath with Finn. Finn releases them from it when they transport him to the Ice Kingdom. After that, they float to the mesosphere to die, which they are excited to do.
They also make a cameo in the beginning of "The Duke," when Finn and Jake throws bottles of magic at a wall.
The most unique of the balloons is an angry balloon, first shown in "Ricardio the Heart Guy" for a party. He later appears in "What is Life?" and watches the other balloons give Finn a ride, but he only floats along with them. He makes another appearance in "The Duke," when Jake throws a potion bottle at the castle.
The balloons are all similar-looking with a variation of colors while the angry balloon is a slightly dull shade of purplish gray. He has an unusually grouchy face while all the other balloons have simple, happy faces. He also has a shriveled nose and small eyes with pupils, which the other balloons do not have.
- The angry balloon resembles Eight-Armed Willy from The Marvelous Misadventures of Flapjack.
- The balloons say "Yay! To the mesosphere! Finally we can die!" even though balloons usually burst in the stratosphere because of the pressure differential.
- The only balloon that remains the same throughout the series is the angry balloon.
- It is revealed by Finn that they are great pranksters, as demonstrated when Finn jumps out of the Ice King's castle and they all pull their strings up, causing Finn to fall, but three other balloons catch him.
We got your back!
I got his wallet!
To the mesosphere!