|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 #55 is the fifty-fifth issue of the Adventure Time comic book.
Finn and Jake discover that it's not just them-everyone in Ooo is trapped in their own little realities!
Finn, Jake, and Marceline make their way through a forest to get to giant BMO, and Marceline notes that this doesn't look like any part of Ooo. Finn thinks talking to BMO will fix things, then encounters a monitor with BMO's likeness, but it says it's actually a representative of the being with the unpronounceable name. Finn asks what the deal with the cowboy world was, and BMO thinks he would like something else. They make the cowboy world collapse, to the other's shock. Then a large hole with moving cables opens up, and BMO tells Finn he needs to jump in, too. Finn and Jake opt to run away, but Marceline is caught by the cables, which start pulling her into a tree hole. BMO says there's a perfect place for her. Finn wants to help her, but Jake tells him to keep running and that Marceline can take care of herself. BMO tells the two that they will find them a good place in BMOWORLD.
Elsewhere, numerous Lemongrabs are running a hospital. The doctor and chief physician yell at each other, then are interrupted by another, who tells the doctor he has to do a surgery. After prepping himself, the doctor asks what's wrong with the patient. The other doctor's say he's sick, and the medicine they used caused him to grow boils. Disgusted, the doctor shoves the patient's bed out the window, and Finn and Jake see the falling patient. Finn figures they should check the hospital for clues and asks the patient if he's okay. The patient starts responding, but stops when he notices that Finn and Jake aren't lemons. At the same time, in a Transylvania-like setting, a traveler ends up at what he believes could be Castle Dracula. Marceline, somewhat dressed like Dracula, greets him and asks just what is going on.
Back in the hospital, Finn wonders if one of the Lemongrabs is the original, as it isn't like the Lemon Kingdom with different lemon people. Jake doesn't know. The Lemongrabs see the two as non-lemons, declare them sick, and put them in hospital beds. Finn and Jake figure that BMO made this world for Lemongrab, and they are soon brought to the doctor. The doctor sees Finn as incurable and sends him down the medical waste chute. He thinks Jake can be cured since he is yellow and prepares for surgery, but Jake doesn't want that. Finn lands safely in the disposal area, but sees that the contents are not medical waste. Jake stretches around to avoid the Lemongrabs' surgical tools and states his and Finn's theory to them: They think that BMO and some kind of magic made this world like a playground for Lemongrab. He asks them why they would want a world that's always so stressful or why someone would think they'd want that. The Lemongrabs ponder this for a moment, but go back to trying to operate. Jake goes out the window and takes the form of a bird. As he flies away, he tells the Lemongrabs to think about what he said, and they realize that he is "free."
At Castle Dracula, a man with an eyepatch asks Marceline to look at an "interesting phenomenon" he found. Marceline knows that he's going to show her a mirror to see if she casts no reflection, proving she is a vampire. The man tries to cover it up, but Marceline reveals that she is a vampire and scares him. He curls up into a fetal position and begs her not to drink his blood. Calling all this dumb, Marceline turns into a bat monster and flies off. Back to Finn, he finds a bunch of pirate-related stuff and remembers that they were pirates before being cowboys. He realizes they rejected that world and BMO put it underground. He then sees a picture of him and Neptr as pirates, which he doesn't remember.
Jake gets tired from flying, but reaches the Candy Kingdom, seeing that it looks a little different. He goes to Princess Bubblegum's room to get her help. He approaches a bed, assuming she's in it, unaware that it's actually a set of beartraps. Bubblegum saves him from the traps and tells him to hide under the bed. Jake asks what's going on, and Bubblegum explains that she's been trapped in a "princess kidnapping loop," in which she gets captured by an evil sorcerer and has to wait for a hero to rescue her. She thinks it's some sort of game, but she found a way around it. The evil sorcerer then arrives to kidnap her, but is sent flying by another trap. Meanwhile, Finn finds giant BMO and manages to get to eye level with them. Back at the Candy Kingdom, Jake and Bubblegum head for the exit. Bubblegum says this is the farthest she's gotten to escaping. Jake asks what normally happens, and Bubblegum tells him that Neptr comes and saves her. She figures that BMO is making fantasy game worlds for everyone and that this one is for Neptr. She opens the door, but they find a wall congratulating them for winning "Secret Princess."
Finn asks BMO why they're changing up Ooo. BMO states that BMOWORLD is for fun and asks Finn what he'd like to play next. Suddenly, BMO is overtaken by the being with the unpronounceable name, saying that input weakens pure vision. Bubblegum and Jake realize that Secret Princess was the game all along and decide to bust out. Marceline shoves away a Frankenstein's monster, saying she doesn't want to be friends, and flies away. Lemongrab questions why he would want stress and chooses to leave the hospital. Finn tells BMO that everyone is a prisoner of a fake world. BMO realizes that nobody likes BMOWORLD, but claims that they will like it and starts to change it again. Finn falls as the earth crumbles, but is caught by Neptr.