A different take could be a love story within the fanfiction. Jonathan falls in love with a vampire girl who has a very different view of the human - vampire relationship. They could face opposition from both the human world and some of the more traditional vampires in Hotel Transylvania. Their love could be a catalyst for change in the way vampires and humans interact in this fictional world.
One idea could be that Jonathan discovers a hidden vampire power within himself. Maybe he starts to have visions of ancient vampire battles and uses this knowledge to help Dracula and his friends in a new crisis at the hotel. For example, he could foresee an attack from a group of vampire hunters and use his unique human - vampire hybrid perspective to come up with a clever defense strategy.
First, research the existing lore of Hotel Transylvania. Know the rules about vampires, how they interact with other monsters, and the overall tone of the movie. Then, develop Jonathan's character as a vampire. Think about how his human qualities will mix with his new vampiric nature. For example, will he still be as clumsy or will he become more suave? Next, create a plot. It could be a simple adventure where he has to prove himself to the vampire community or a more complex story about identity.
Maybe in the fanfiction, there's a plot where Dracula and Jonathan have to team up to save Mavis from an ancient vampire curse. They'd have to travel to different parts of the Transylvanian underworld and face all sorts of spooky creatures along the way. It would show their growing friendship and mutual respect for each other.
Johnny becoming a vampire in the Hotel Transylvania universe could lead to some really interesting scenarios. For example, he might struggle with adapting to vampire life while still maintaining his human charm. He could have a hard time getting used to the nocturnal lifestyle and the need to drink blood, which would be a big change from his regular human habits.
One idea could be that Naruto is on a mission in a world similar to that of Hotel Transylvania. He could encounter the unique creatures there and have to team up with some of the hotel residents, like Dracula, to defeat a common enemy. Maybe an evil ninja has found a way to drain the life force of the supernatural beings in the hotel and Naruto's skills are needed to stop it.
Another fanfiction could involve a spell gone wrong in the Harry Potter universe that transports some of the Hogwarts students to Hotel Transylvania. The students then have to adapt to this new and strange place, and they could teach the vampires and other creatures about magic from their world, while also learning about the unique abilities of the hotel's inhabitants. For example, the werewolves in Hotel Transylvania could compare their transformation experiences with those of the werewolves in the Harry Potter world.
One idea could be a story about a new character who arrives at the hotel during the events of the third movie. This character could have a special power that both helps and causes chaos among the hotel guests. For example, they might be able to communicate with sea monsters in a unique way, leading to some hilarious misunderstandings.
One idea could be that Naruto, with his godlike powers, accidentally ends up in the Hotel Transylvania universe. He could befriend the monsters there and use his powers to help them with some kind of threat that they are facing, like a powerful enemy who wants to destroy the hotel and the peace between humans and monsters. His shadow clone jutsu could be used in creative ways, like having clones help with the hotel's daily tasks while he goes on adventures with Dracula's daughter.
One idea could be a fanfiction about Mavis and Dracula going on an adventure together to discover a new magical place for the hotel. This would focus on their relationship and the expansion of the hotel's world.
One possible plot could be that Johnny is accidentally turned into a vampire. He then has to deal with the shock of his new state while also trying not to worry his human family. He could rely on Mavis and Dracula for support and guidance in learning about his new powers and limitations.
A third idea could be a crossover where there is a big tournament. Characters from both Naruto and Hotel Transylvania participate. Naruto and his friends use their ninja techniques, and the monsters from Hotel Transylvania use their supernatural abilities. It would be an exciting and unique battle where the two different worlds' combat styles collide.