What are some interesting plot ideas for a Coraline and ParaNorman fanfic?

Maybe a powerful demon that has been lurking in the shadows of both universes. This demon is attracted by the unique magic in both Coraline's and Norman's worlds. It starts to possess the people and creatures in both places, and Coraline and Norman must find a way to exorcise it. The demon could be very cunning, disguising itself as friendly beings at first.

Some interesting ideas for Coraline fanfiction could involve Coraline's relationship with her parents after the events of the movie. Maybe she tries to get them to understand a little bit of the magic she experienced without scaring them. Or you could write about Coraline meeting other children who have had similar experiences with other worlds. This could lead to a whole new adventure as they try to figure out the secrets behind these strange worlds.

One idea could be a crossover with "Alice in Wonderland". Coraline could fall through a different kind of portal and end up in Wonderland. She could meet the Cheshire Cat and have some interesting conversations about the strange worlds they both come from. Another idea is a crossover with "The Nightmare Before Christmas". Coraline might visit Halloween Town and be both intrigued and a bit scared by the spooky inhabitants.

One idea could be that Norman and Aggie team up to solve a new mystery in Blithe Hollow. Maybe there are strange disappearances that only their combined abilities can figure out. Another plot could be Aggie wants to experience modern life and Norman has to show her around, leading to some comical and heartwarming situations. And they could also face a new supernatural threat that is more powerful than the ones they've encountered before, forcing them to rely on each other more than ever.

An idea could be that the button eyes are a portal to another dimension within the other world. Coraline discovers this accidentally and has to navigate through this new and even stranger place. It would add a new layer of mystery and adventure to the story.

Another plot could revolve around the characters having premonitions of the events that are going to occur in the quarry. They then have to decide whether to trust these visions and how to act upon them. This could add a whole new layer of suspense and mystery to the story.

One idea could be a time - travel plot. The Backyardigans accidentally find a magical object in the backyard that sends them to different eras in history. They could have to work together to find their way back home while also learning about the different time periods. For example, they might end up in the prehistoric era and have to deal with dinosaurs.

One idea could be a story where one of the dalmatian puppies gets lost during a family outing and has to find its way back home, facing various challenges along the way.

One idea could be exploring the backstory of a minor character in the Bioshock universe. For example, a splicer's journey before they became spliced. It could show how they were once an ordinary citizen of Rapture and what led them to make the fateful decision to use ADAM. Another plot could focus on an alternate timeline where the protagonist makes different choices. Maybe they side with the wrong faction and have to deal with the consequences. A third idea is a story centered around a new type of plasmid that has unexpected effects on the user and how it impacts the power dynamics in Rapture.

Another plot could involve the creation of a female monster. In the original, Victor Frankenstein was hesitant to create a female. A fanfic could explore what would happen if he did. Maybe the two monsters would have a complex relationship, and together they would try to find a place in the world that would accept them.