Fionna and Cake Finally Solved One of Adventure Time’s Last Mysteries

Against all odds, Adventure Time managed to resolve almost every single mystery by the time it ended. We learned how the Land of Ooo rose up in the aftermath of nuclear war. We found out that Jake the Dog was actually the child of an evil, shapeshifting alien, and we traveled to the secret island where Finn the Human was born and other humans still lived in secrecy. But one mystery remained, until now.

In Adventure Time: Fionna and Cake Episode 4, the Max spinoff sequel finally explains where its titular characters actually came from. Luckily, we had a chance to talk to showrunner Adam Muto, who answered all our questions about that one wild scene.

Warning: Spoilers ahead for Fionna and Cake Episode 4 🙀

Fionna and Cake in another multiverse.

Max

In the most recent episode of Fionna and Cake, the two main characters are summoned by Prismo (a wish-granting and multiverse-observing space god) to his Time Room (a yellow cube floating somewhere beyond time and space that also contains a hot tub). Fionna and Cake have escaped their universe and landed in Ooo, and it’s Prismo’s job to send them home. Except, this one is personal. Turns out, Prismo actually created Fionna and Cake as his own multiverse after he got bored of doing the same thing for other people.

Of course, this wasn’t always the plan for Adventure Time’s creators. In the first “Fionna and Cake” episode, released back in 2011, the duo is revealed to be in-universe fanfiction written by Ice King.

“The idea of them being fanfiction is from the very first episode,” showrunner Adam Muto tells Inverse, “but making it somebody else’s fanfiction came a bit later.”

Prismo in an earlier Adventure Time episode.

Cartoon Network

In a much later Adventure Time episode, it was revealed that someone else actually implanted the Fionna and Cake multiverse inside Ice King’s head. Now we know that someone was Prismo, who reveals in Fionna and Cake that he used Ice King’s empty brain as a hard drive to hide his secret creation. When Ice King lost his magic powers in the series finale and reverted to a regular human, Fionna and Cake’s universe lost its magic too.

For Muto, this twist has been in the works for a while, but he didn’t have a chance to make it a reality until now.

“After Prismo was introduced as a character, it just kind of shifted in that direction,” he says. “It was something we had in mind, but we didn’t think we’d ever really pay it off within the run of the show. It would’ve been cool, but we just didn’t have the episode count to overexplain one element of what Fionna and Cake were.”

Ice King gets the Fionna and Cake universe implanted in his brain, as depicted in Aventure Time Season 9 Episode 12, “Fionna and Cake and Fionna.”

Cartoon Network

Ultimately, it was important that Fionna and Cake became something more than the creation of an insane wizard.

“I resisted the idea of them being just fanfiction from Ice King because it would limit them forever to just being his interpretation of Finn and Jake and him being obsessed with them,” Muto says. “Which was funny as a joke but it felt weird after a while. It felt like we’re kind of boxing them in.”

As for the pink laser, Muto says it’s a direct reference to another sci-fi classic: “That was inspired by Valis, the novel by Philip K. Dick. There’s a pink laser that transmits information in that one.”

Fionna and Cake is streaming now on Max.