A crossover with Sonic the Hedgehog would also be cool. Imagine Cuphead and Sonic racing through zones, with Cuphead having to use his quick dodging abilities to keep up with Sonic's speed. And maybe they team up to stop Dr. Robotnik from taking over their combined worlds.
One idea could be a Cuphead crossover with Super Mario. Cuphead and Mugman could find themselves in the Mushroom Kingdom, facing off against Bowser's minions alongside Mario and Luigi. They could use their unique shooting skills to help in battles.
One idea could be that the characters from Cuphead end up in the world of Batim. Cuphead and Mugman might be mistaken for new ink creations in the studio. They could then have to deal with the strange and often menacing creatures in the Batim world while trying to find a way back to their own.
One idea could be exploring Cuphead and Mugman's childhood. Maybe they had a special adventure before the events of the game. Another idea is to create a fanfiction where they meet new characters in a different part of the Inkwell Isles that has a unique theme, like an underwater world. A third idea could be a story where Cuphead has to face his fears without Mugman by his side for a change.
Another interesting concept is an OC that is a traveling musician in Inkwell Isles. This OC could meet Cuphead and Mugman during their travels and join them on their quests. They could use their music to soothe enemies or even as a form of attack, like creating sonic waves that stun bosses. It would add a unique element to the existing Cuphead world.
Maybe in the fanfiction, there's a powerful villain who has stolen an important item from both Bendy's world and Cuphead's world. Bendy and Cuphead meet by chance and realize they have a common enemy. They start their journey together. Cuphead teaches Bendy some of his acrobatic moves, and Bendy shows Cuphead how to use the environment to his advantage with his ink.
Perhaps Bendy and Cuphead are forced into a competition by a mysterious villain. They start off as rivals but gradually realize that they need to work together to defeat this common foe. This could involve them using their unique abilities, Bendy's flexibility and Cuphead's shooting skills, in creative ways.
One plot idea could be Djimmi and Beppi teaming up against Cuphead. They might create a series of wacky challenges in their own magical and carnival - themed worlds respectively, and Cuphead has to go through them to get a special item. Another idea is a story where Djimmi and Beppi start as rivals, each trying to outdo the other in terms of magic tricks or carnival attractions, but then they realize they can be more powerful together.
One plot idea could be that Cuphead and Baroness have to team up against a greater evil in the Cuphead world. Maybe a new powerful devil - like character shows up and they realize they need each other's skills to defeat it.
One common theme is the clash of art styles. Since Cuphead has its distinct 1930s - style animation look, when it crosses over with other franchises like modern - day 'Adventure Time' or 'My Little Pony', the contrast in art and design becomes a central focus. Another theme is the adaptation of gameplay elements. For example, in a crossover with 'Mega Man', the platforming and shooting mechanics from both universes are combined in new and interesting ways.
The Devil from Cuphead could be really interesting. Imagine him showing up in Bendy's world. His menacing presence and powers would be a huge threat. Bendy and his friends would have to figure out how to deal with this new and powerful foe. And the Devil could also be interested in Bendy's world for some dark purpose, like trying to corrupt it further.
One plot idea could be King Dice getting into a tricky situation where he has to choose between loyalty to the Devil and his own sense of right and wrong. Maybe he discovers a plan of the Devil's that he doesn't agree with, like a scheme to cheat more souls out of the Inkwell Isles' inhabitants in a really unfair way. Another idea is a backstory for King Dice that shows how he became so close to the Devil in the first place. It could involve his own ambitions and how the Devil promised to fulfill them. A third plot could be about a character from the Cuphead world trying to save King Dice from the Devil's influence, leading to a series of challenges and adventures.