ELI5: Explain Like I'm 5

Alternative universe (fan fiction)

Okay kiddo, you know how sometimes we like to make up stories in our heads or tell stories about make-believe characters like superheroes? Well, sometimes people take those stories and change them a little bit to create a whole new version of the story, as if it happened in a different world.

Imagine you have a favorite TV show, like Spongebob Squarepants. Now, imagine you start to wonder what would happen if Spongebob was a detective trying to solve a mystery, instead of just working at the Krusty Krab. That's kind of like what people do with fan fiction - they take a story or character they already love and imagine what would happen in a different version of their world.

It's important to remember that fan fiction is just for fun and not real. It's like doodling or making up stories with your friends. People who write fan fiction aren't trying to change the original story, they just have fun imagining different possibilities.