What are some interesting plot ideas for Danny Phantom and Supernatural crossover fanfiction?

One idea could be that Danny and the Winchester brothers team up to fight a ghost that is causing chaos in both the Ghost Zone and the human world. Maybe it's a powerful entity that has the ability to cross between dimensions easily.

One idea could be that Danny's ghost powers start to malfunction in the TMNT's dimension, causing strange ghostly events that the turtles have to help him fix. Another could be a villain from Danny's world teams up with one of the TMNT's foes, forcing the two groups to work together. Maybe Danny accidentally gets sent to the sewers where the turtles live and they initially mistake him for a new type of mutant.

Well, there could be a story where Danny's ghost sense starts acting up in the Naruto world. It turns out that there are some spirits there that are similar to the ghosts in his world. Naruto thinks Danny is crazy at first but then they discover that these spirits are tied to an ancient curse. Together, they have to find a way to break the curse. Danny uses his ability to communicate with ghosts to learn more about the spirits, and Naruto uses his determination and strength to face any physical challenges that come their way.

A possible plot is that a powerful ghost in Danny's world has a connection to an ancient demon in Inuyasha's world. This connection is causing chaos in both worlds. Danny and Inuyasha meet and initially are at odds because they don't trust each other. But as they start to learn about the threat they face together, they begin to work together. Danny uses his energy blasts and Inuyasha uses his Tessaiga to fight the combined forces of the ghost - demon entity.

Maybe Danny gets transported to a different dimension where there is a harem - like society. The local girls there are intrigued by his ghost powers and his heroic nature. They start following him around, and he has to figure out how to deal with their attention while also trying to find a way back home. Some of the girls might be from different species, which could add more interesting elements to the story, like different cultural norms regarding relationships.

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 Danny and Kim have to team up to stop a new villain who has the ability to manipulate both the ghost world and the regular world. This villain could be causing chaos in both dimensions, and only by combining their unique skills can they hope to stop it.

One idea could be that Danny's ghost powers somehow interact with the dragons in HTTYD. For example, his intangibility might make him able to pass through dragon fire without getting burned, and this could be a crucial skill when dealing with a new, more dangerous breed of dragons. Another idea is that Danny gets transported to the world of HTTYD and has to use his ghostly abilities to fit in and help the Vikings. Maybe he can use his flight ability to race against the dragons, which would be an exciting plot point.

One idea could be Danny Phantom teaming up with characters from other Nickelodeon shows to fight a common supernatural threat. For example, he could join forces with the Teenage Mutant Ninja Turtles. They could use their unique skills, Danny with his ghost powers and the Turtles with their ninja skills, to take on a powerful ghost - mutant hybrid enemy.

One idea could be to explore how Danny's ghost powers interact with the dark and tortured world of 'The Suffering'. Maybe he gets trapped in that nightmarish realm and has to use his unique abilities to survive and find a way out. Another idea is to have some of the tortured souls from 'The Suffering' cross over into Danny's world and how he deals with them while keeping his identity as a half - ghost a secret.