Another idea is a story about Danny and Star accidentally swapping powers. Danny has to deal with Star's magic while Star tries to control Danny's ghost abilities. It could be a comical yet challenging situation for both of them as they learn to adapt.
A more in - depth idea could be a fanfiction where Danny and Star meet during a multiverse - spanning event. They initially clash due to their different approaches to handling threats, but as they get to know each other better, they realize they can learn a great deal from one another. Danny could teach Star about the scientific aspects of his powers, while Star could introduce Danny to the more esoteric and magical side of her world. This could lead to a deep friendship or even a romantic relationship as they face various challenges together in different dimensions.
One idea could be that Danny Phantom somehow gets transported to the Star Wars universe. Maybe he uses his ghost powers to help the Jedi or the Rebels. For example, his intangibility could be useful in sneaking past enemy defenses.
One idea could be that Danny gets an illness that affects his ghost powers. For example, he might start losing control over his intangibility or invisibility. This could lead to some really comical or dangerous situations. Another idea is that his friends try to find a cure for his strange ghost - related illness while also keeping it a secret from the town.
One idea could be a crossover where the characters from Danny Phantom and LoliRock team up to fight a common supernatural threat. Maybe the ghosts from Danny's world are being influenced by a dark magic from the LoliRock universe, and they have to combine their powers to stop it.
A more complex plot could be that there is a prophecy about a union between a half - ghost and a magical being like Star. Danny and Star initially don't believe it, but as they keep crossing paths and helping each other out, they start to see that there might be something more to it. However, there are forces that oppose this union, thinking it will disrupt the balance between the human world, the magical world, and the Ghost Zone. So they have to fight against these forces while also coming to terms with their own feelings.
One idea could be exploring Danny's relationships in a different way. For example, how his friendship with Sam and Tucker might develop if they faced a new supernatural threat. Another could be a story where Danny discovers a new power and has to learn to control it while dealing with school and his ghost - fighting duties. And perhaps a fanfiction where Danny travels to an alternate dimension within the Danny Phantom universe.
A great fanfiction idea could be a time - travel story within the Danny Phantom Phantom Planet universe. Danny somehow gets sent back in time to before he became a half - ghost. He has to figure out how to get back to his own time while also dealing with the knowledge he has of the future. This could lead to some really interesting interactions with his past self, his family, and friends. And he might accidentally change things in the past that could have a huge impact on the future of the Phantom Planet.
A possible plot could be that there is a ghostly music competition in the Ghost Zone. Danny enters to stop some sort of dark plot related to it, and Ember is also a participant. Along the way, they form an alliance and their relationship blossoms as they work together to uncover the mystery behind the competition.
One idea could be that Danny somehow gets transported to the Digital World. He uses his ghost powers in unique ways to survive and help the Digimon. For example, his intangibility might be useful against certain digital threats that the Digimon can't deal with on their own.
One idea could be that Skulker, instead of always hunting Danny, teams up with him to face a new and powerful ghost threat that is endangering the entire Ghost Zone. This would force them to put aside their differences and use their unique skills together.
One idea could be that Danny's ghost powers are misinterpreted by Batman as some new kind of meta - human ability. Danny might end up being hunted by Batman at first until they realize they can work together to fight a common enemy like a powerful ghost that has escaped into Gotham.