Well, you might find yourself transported as a character with a special power. For example, the ability to see through the illusions that the strange creatures in Gravity Falls create. This would put you in a unique position to help Dipper and Mabel solve mysteries. Or perhaps you end up in a parallel version of Gravity Falls where the rules are slightly different, like the gravity is reversed in certain areas. You'd have to adapt quickly to survive and figure out how to get back to your own world.
One idea could be arriving in Gravity Falls right during the Weirdmageddon event. You could team up with the Pines family to fight Bill Cipher. Another could be getting transported into the past of Gravity Falls, like when the town was first founded, and uncovering long - lost secrets. Maybe you become a new character in the Mystery Shack and have to deal with the daily weirdness that comes with it.
One plot idea could be that the characters from Gravity Falls enter the Pokemon world. They could go on a journey to become Pokemon trainers, facing challenges like gym battles and Team Rocket - like villains. For example, Dipper and Mabel could each catch their favorite Pokemon and compete in Pokemon contests.
One idea could be that Dipper and Mabel end up in the Undertale universe. They might meet Sans and Papyrus. Dipper could be intrigued by the magic system in Undertale and try to study it, while Mabel would probably befriend the friendly monsters right away. Maybe they get involved in the conflict between humans and monsters in the Undertale world and use their Gravity Falls knowledge to find a new solution.
Another interesting plot could be that there's an ancient vampire curse in Gravity Falls, and Dipper gets caught up in it. He has to find a way to break the curse before it's too late, and in the process, he discovers more about the history of the town and its connection to vampires. This could involve teaming up with Mabel and other characters from the show to solve the mystery.
One idea could be that a character accidentally drinks the love potion and falls for the wrong person, like Dipper falling for Gideon, creating a chaotic and humorous situation. Another could be a character using the love potion to win a popularity contest in Gravity Falls, but things go awry when too many people fall for them at once. Maybe a character tries to use the love potion to make their crush notice them, but it backfires and makes the crush avoid them instead.
Perhaps there is an ancient evil that threatens both Gravity Falls and Hilda's world. The characters need to combine their unique skills and knowledge. Dipper's knowledge of the strange and supernatural from Gravity Falls, along with Hilda's experience with the magical creatures in her world, would be crucial. They could start by gathering allies from both worlds, like Wendy and David. Then, they embark on a journey to find the source of this evil and a way to stop it. This would involve a lot of exploration, mystery - solving, and character development as they learn from each other.
One idea could be that Danny Fenton and the Mystery Twins, Dipper and Mabel, cross paths while investigating a supernatural mystery that involves both the Ghost Zone from Danny Phantom and the strange anomalies in Gravity Falls. Maybe a powerful ghost has escaped into Gravity Falls and is causing chaos there, and Danny has to team up with the twins to stop it.
One idea could be that the characters from Rugrats somehow end up in Gravity Falls. Maybe the babies follow a strange glowing bug that turns out to be a magical creature from Gravity Falls. And Tommy could befriend Dipper, and they start exploring the mysteries of Gravity Falls together. The Rugrats' naivete could add a new comical element to the Gravity Falls mysteries.
One idea could be that Dipper and Mabel from Gravity Falls end up in the SVTFOE universe. They could team up with Star to battle some sort of interdimensional evil that threatens both their worlds. Maybe they discover a connection between the strange creatures in Gravity Falls and the magic in SVTFOE.
One idea could be a crossover where Danny Phantom visits Gravity Falls. He could use his ghost powers to help the Pines family solve some of the mysteries there, like dealing with a supernatural entity that's beyond the normal Gravity Falls weirdness. Maybe he teams up with Dipper to fight a ghostly creature that has been causing trouble in the forest.
A really cool plot might be that the forces of Hell in Supernatural are trying to take over Gravity Falls because of its unique supernatural properties. Sam and Dean, along with Dipper and Mabel, would need to use their combined knowledge and skills. Sam's research abilities and Dean's combat skills, along with Dipper's knowledge of the town's secrets and Mabel's out - of - the - box thinking, to stop the demonic invasion.