Themes are important too. Gravity Falls has themes of mystery and family. If it's crossed over with a show like Avatar: The Last Airbender, the fanfic should blend the themes of bending and the mystery of Gravity Falls well. And of course, the fanfic should stay true to the essence of Gravity Falls. The unique humor, the creepy elements, all of that should be there in the crossover.
The world - building in a crossover fanfic is crucial. If it's a Gravity Falls and Harry Potter crossover, how do the magic of Hogwarts and the weirdness of Gravity Falls co - exist? It should be detailed and make you feel like both worlds are real and interacting in a logical way. Also, the pacing of the story should keep you engaged, not too slow or too fast.
Character interactions are key. You want to see how the characters from different shows blend together. For example, if it's a crossover with Scooby - Doo, seeing how Shaggy and Dipper would react to the mysteries in Gravity Falls. Also, a good plot that makes sense for both universes. It can't just be a random mash - up.
One idea could be that the ponies from MLP accidentally end up in Gravity Falls. Twilight could be intrigued by the strange anomalies in Gravity Falls and try to study them with Dipper's help. Maybe Pinkie Pie's party - planning skills could be used to liven up Gravity Falls' rather spooky events.
The colorful and magical world of Equestria from MLP could be juxtaposed with the spooky and mysterious Gravity Falls. You could have parts of Gravity Falls, like the Mystery Shack, appear in Equestria. Maybe the ponies think it's a new kind of magical building. Or, have the Gravity Falls forest start to show up in Equestria, with its strange creatures and anomalies.
One possible plot could be that Dipper and Mabel visit Beach City while on a road trip. They meet Steven and the Gems. The Mystery Shack's oddities could interact with Gem magic in strange ways. For example, a Gem artifact might be mistaken for a regular Mystery Shack item and cause chaos when activated.
The merging of the two different settings. Gravity Falls has its own spooky and mysterious forest and town, while Undertale has the Underground with all its unique areas like Snowdin and Hotland. When these two settings are combined in a fanfic, it creates a whole new world full of possibilities. For instance, a fanfic might have a scene where the characters are exploring a part of the Underground that has been influenced by the mystery of Gravity Falls. This could lead to some really unique and unexpected story developments. It also allows for a lot of creativity in terms of how the rules of both universes interact.
Sure. One great Gravity Falls crossover fanfic is 'Gravity Falls and Steven Universe: Crystal Falls'. It combines the mystery of Gravity Falls with the magic of Steven Universe in a really interesting way. The characters interact in a believable manner and the plot is engaging.
Mabel would be excited to meet the Winchester brothers. She might try to get Dean to tell her all his hunting stories and would probably try to knit them some cool accessories. She could also introduce Sam and Dean to Waddles. Dipper would be a bit more cautious around them at first, but as they started working together, he would respect their skills and knowledge. The characters would need to learn to trust each other quickly since they come from different worlds but are facing similar threats.
One main theme is the clash of different worlds. 'Worm' has a more urban, superpower - filled setting, while 'Gravity Falls' is a small, mystery - ridden town. When they cross over, it's about how these two very different environments and the characters within them interact.
Perhaps the character interactions are a key concept. Imagine Dipper from Gravity Falls meeting Star from SVTFOE. Dipper's inquisitive nature and Star's bold and impulsive personality could lead to some really fun and unexpected adventures. They might team up to solve a mystery that involves both the Gravity Falls' mystery and the magic of SVTFOE.
Definitely Dipper and Mabel from 'Gravity Falls' would be main characters. And from 'The Replacements', Todd and Riley could be the main ones. They would be the ones driving the plot forward as they interact with the new and strange world or characters they encounter.
A possible plot is that the 'Gravity Falls' characters accidentally open a portal to the world of 'The Replacements'. The Replacements' characters then have to adjust to Gravity Falls' weirdness. There could be a conflict where the Gravity Falls' villains try to take advantage of the new arrivals, but they all end up working together to save both their worlds.