One possible plot could be that Wanda's pregnancy brings a new dynamic to the Hotel Transylvania. The other monsters are excited yet also a bit worried about how a new baby monster will fit in. Dracula might offer his wisdom on raising a little one, as he has experience with Mavis. Wanda's partner would be extra protective, and there could be comical scenes of him trying to prepare the perfect nursery within the hotel, while also dealing with the various antics of the other hotel guests.
A fanfiction might focus on the challenges Mavis faces during her pregnancy. Since she is a vampire, there could be unique vampire - related health concerns. She might need to find a special diet that suits both her and the baby. Also, she has to deal with the pressure of being the first vampire - human hybrid to have a child in a long time. The story could detail her journey to find solutions to these problems while still being excited about the new life on the way.
It could strengthen some relationships. For example, her relationship with her partner would likely become deeper as they prepare for the baby. Her friends in the hotel, like Frankenstein and his bride, might become more protective and offer their support. Dracula, as the owner of the hotel, would probably become more involved too, seeing Wanda's baby as part of the hotel's future family.
One possible fanfic idea could be that Mavis discovers she's pregnant and there's a lot of chaos in the hotel as everyone tries to prepare for the new addition. Dracula might be overprotective and start making all kinds of crazy arrangements to keep Mavis and the unborn baby safe. The other monsters in the hotel could also have their own reactions, like Frankenstein being excited to have a new little friend to play with in the future.
Well, she could start having strange cravings. Maybe she'd crave human food that Johnny likes, which would be really odd for a vampire. This could lead to some funny scenes where she tries to get the kitchen staff to make these strange combinations.
Well, in this kind of fanfic, there could be a lot of comical situations. For example, the werewolves in the hotel might offer to be guards for Mavis, but they end up being a bit too overzealous and accidentally causing small disasters. And Mavis could start to develop new powers during her pregnancy that she has to learn to control.
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.
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.
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.
In a fanfiction of Dennis and Winnie, perhaps they decide to explore the outside world. Winnie, being a vampire, has to protect Dennis from the sun. They meet some friendly humans who are surprisingly accepting of them. Dennis starts to realize that he can be a bridge between the human and vampire worlds. They have a lot of fun, like trying human food for the first time and sharing vampire stories with their new friends.