What could be an interesting plot for a 'Harry Potter meets Gaster' fanfic?

One possible plot could be that the Hogwarts students are on a field trip when they accidentally stumble into the world of the Enterprise. Harry and his friends could help the Enterprise crew deal with a magical threat that the crew's technology can't handle. For example, a dark wizard has created a spell that is causing chaos on the Enterprise and only magic can reverse it.

Definitely Harry and Gaster. Harry is used to the magic in his world, while Gaster has his own set of abilities. Their meeting would be full of confusion, curiosity, and perhaps a bit of wariness. Another interesting interaction could be between Hermione and Gaster. Hermione would be eager to learn about Gaster's knowledge and would probably bombard him with questions.

Well, perhaps Gaster has lost his memory and believes he is a wizard in the Harry Potter world. He could start to regain his memories slowly as he experiences different magical events. For example, when he encounters the Forbidden Forest, it could trigger some memories related to his own world. And the characters in Harry Potter would be both intrigued and cautious about this strange new 'wizard' who seems to have such different ways of using magic.

One possible plot could be that there is a rift in the multiverse which causes Danny Phantom to cross paths with Gaster. Gaster's knowledge of the multiverse and Danny's ability to traverse different dimensions in his ghost form could be combined. They start to explore the reasons behind this rift and discover that an evil entity is trying to merge different realities for its own malicious purposes. Danny and Gaster then have to use their unique skills to stop this entity and close the rift to restore the balance of their respective universes.

Perhaps Harry is on a trip outside of the wizarding world when he comes across Venom. At first, they are at odds as Venom views Harry as a potential threat. But as they get to know each other, they find out that they both have a sense of justice. Venom is impressed by Harry's magical abilities and Harry is intrigued by Venom's strength. They then team up to take on a common enemy, like a powerful sorcerer who is using dark magic to create chaos in both the Muggle and wizarding worlds.

Maybe in the fanfiction, Harry accidentally enters a parallel dimension where Lily is still alive. Here, Lily discovers that Harry is her future son. She might take him under her wing and train him in a different way of magic, one that was perhaps forgotten in Harry's own time. This could lead to Harry having unique powers and a different approach to dealing with the Dark Arts and his enemies.

A plot could involve Sherlock being a wizard all along but not realizing it until he meets Harry Potter. He has been using his logical mind to do what he thought was normal detective work, but it was actually his latent magic powers at play. Together, they could solve crimes in both the Muggle and wizarding worlds, using Sherlock's methods and Harry's knowledge of magic spells and potions.

One possible plot could be that the magical creatures in the Harry Potter world start to show up in Forks. For example, a hippogriff might fly over the forest near Bella's house, causing chaos among the vampires and werewolves. The wizards from Hogwarts could come to investigate these strange new creatures that seem to have a different kind of magic than what they're used to. Harry, Hermione, and Ron could find themselves in the middle of the vampire - werewolf feud, trying to figure out how to keep the peace and also protect the muggles in Forks from getting too involved in this new magical mess.

In this fanfiction, a new teacher arrives at Hogwarts who has a passion for both magic and glee. This teacher decides to start a glee - like club at Hogwarts. Harry and his friends are intrigued and join. They discover that music has a special power in the wizarding world. It can be used to unlock hidden magical abilities. The club then prepares for a big magical glee competition against other magical schools, with each performance having a unique magical twist.

Well, perhaps Byako is a being from another dimension. In the 'Harry Potter meets Byako fanfiction', Byako could accidentally cross over into the Harry Potter universe while being chased by some sort of other - dimensional foe. Harry and his friends could help Byako hide from this enemy while also learning about different forms of magic from Byako's world.