A Danny Phantom and The Last of Us fanfiction might focus on the characters from both universes interacting. Joel and Ellie could meet Danny and his friends. Danny could use his powers to protect them from the various threats in The Last of Us world, like clickers. It could also explore how the different rules of the Danny Phantom world, such as the existence of the Ghost Zone, would impact the already complex world of The Last of Us.
It could be a wild crossover. Danny Phantom could use his ghost powers to help the Avengers in the final battle of Endgame. Maybe he could phase through enemies and surprise them. His intangibility and invisibility would be great assets.
First, you need to understand the core elements of both universes. Know Danny Phantom's powers, his friends, and his enemies. Also, be familiar with the post - apocalyptic world, the types of infected, and the relationships in The Last of Us. Then, think of a unique plot that combines these two worlds. For example, a portal from the Ghost Zone could open in The Last of Us world.
A fanfiction could also explore a scenario where Peter Parker gets some ghostly powers similar to Danny's due to an experiment gone wrong. He then has to learn how to control these new powers while still being Spiderman. Danny could come to help him understand and master these powers.
One idea could be that the Joker somehow finds his way into the Danny Phantom universe. Maybe he teams up with one of Danny's villains, like Vlad, thinking they can cause more chaos together. They could plan to use Danny's ghost powers for some really wild and dangerous stunts across both the human and ghost worlds.
A more complex fanfiction could be about Starfire getting stuck in Danny's world. She has to adapt to living in a world where ghosts exist and not everyone is as friendly as in her own. Danny helps her understand the rules of his world, and in the process, they develop a strong friendship that could potentially turn into something more romantic as the story progresses.
One idea could be that Danny Phantom gets transported to Poison Ivy's world. He has to deal with her plant - based powers while trying to find a way back home. Maybe he teams up with her against a common enemy who is threatening both the Ghost Zone and the natural world.
Another fanfiction concept is that a character from The Walking Dead dies and becomes a ghost like in Danny Phantom's world. Danny has to help this new ghost come to terms with their situation while also dealing with the zombie apocalypse around them. This could explore themes of death, acceptance, and survival all at once.
One idea could be that Danny Phantom accidentally crosses paths with the Grim Reaper. Maybe the Grim Reaper is after a ghost that Danny has befriended, and Danny has to convince the Grim Reaper that the ghost has a good reason to still be around. For example, the ghost could be helping Danny protect Amity Park from other more malevolent ghosts.
One idea could be that Danny Phantom gets transported to the Spider - Man universe. He could use his ghost powers to help Spider - Man fight villains that are a bit more supernatural in nature, like Mysterio when he's using his illusions. Danny could phase through objects to avoid attacks and then surprise the bad guys.
In this fanfiction, it could be that Danny Phantom meets a Danny Phantom from a parallel fan - made story. At first, they don't trust each other. But as they learn more about each other's worlds, they realize that there are some common elements that are being threatened. It could be that a powerful ghost is trying to rewrite all the fanfic universes related to Danny Phantom. So, they must combine their strengths and knowledge to stop this from happening.