|The following information is from the Adventure Time comic book series. It may not be part of the same canon or continuity as the animated series.|
Adventure Time #6 is an issue of the Adventure Time comic book. It features part one of a story featuring Princess Bubblegum's time machine.
The story starts with Princess Bubblegum in her lab working on an alarm clock. She then reveals her bigger accomplishment, a real time machine. Finn and Jake burst in and ask about it, and when the princess explains, Jake tries to steal it so he can teach his baby self how to be cool, but his hopes are quickly dashed when the princess explains that the machine can only travel back to the point when she created it.
Jake complains, but then presses the button with everyone holding on to the machine, and they successfully travel 90 seconds into the past-the moment when the machine was finished. Jake then wrecks PB's lab twice while she tries to explain how it all works, essentially calling it a do-over button, and Jake uses the machine again twice. PB then warns him that it's for emergency use only and nothing else, which Jake ignores as he messes up her name on purpose to use it again. PB states that he can't use it for that, just as her alarm goes off for her to go to the Royal Court.
After she's gone, Jake proposes that they go out and cause some emergencies so they can use it again, but loses a game of rock-paper-scissors with Finn about it. They sit around for a long time, until Jake realizes that if only he touches the device, then only he will travel back in time. He uses the device, and redoes everything, only this time he wins the rock-paper-scissors game. He and Finn go out and try to cause some emergencies, but Jake stubs his toe, so he uses the machine again. Jake causes a time travel spree to accomplish things, like finishing a crossword puzzle, eating large amounts of cake, etc. or for no reason before stopping.
Later that evening as PB return from the Royal Court, she finds a note from Jake saying "Nothing crazy happened." She then checks the hidden usage counter, and finds that overall, the machine was used 88,121 times before Jake stopped. This ticks off the princess, who realizes she had to give her speech over and over again 88,121 times. She then realizes her mistake in trusting a 13 year old boy (Finn) and his dog (Jake) with the power of time travel. She finally destroys the device with a princess smash, and leaves. Jake is then revealed to be creeping in the window, and says that he messed up too big to not rewind it all. He starts to try to fix the machine as the comic ends.
In "Level 99" by Anthony Clark, Jake and BMO make a movie to inspire Finn to beat a video game. Finn has been stuck at Level 99 of Wizards Wars for many weeks. Jake and BMO show Finn a movie they made. It shows Jake as Sir Fireball and LSP as an enemy. However, LSP doesnt like her character and starts complaining. Ice King then arrives and insists on being in the movie. Finn then says that the movie has inspired him to beat the game. When Finn asks what happened to his saved game, BMO says that he has deleted it to have enough memory for the movie. Finn is bummed out by this, but Jake encourages him by saying that Finn gets to play the entire game again. Finn is delighted by this.