One interesting Danny Phantom MLP fanfiction could be one where Danny's ghost powers interact in unexpected ways with the magic in the MLP world. For example, he might use his intangibility to pass through magical barriers in Equestria that ponies can't. Another could be a story where Danny has to team up with the Mane Six to stop a common enemy that is threatening both his world and the world of MLP.
You can try websites like FanFiction.net. It has a large collection of fan - made stories, including those that combine Danny Phantom and MLP. Another option is Archive of Our Own (AO3). It's known for its wide variety of fanfiction, and you're likely to find some interesting Danny Phantom MLP crossovers there.
Perhaps there is a magical artifact in the MLP world that has the power to disrupt the balance between the living and the dead. Danny Phantom senses this disturbance and travels to the MLP world. Applejack, being the responsible pony she is, gets involved. They have to go on a quest to find the artifact and keep it safe. During their journey, they face many challenges, like dealing with other ponies who don't trust Danny at first, and they also have to overcome the obstacles set by the villains who want to use the artifact for their own evil purposes.
I'm not sure of specific fanfics that combine all three, but you could start by checking out fanfiction.net or Archive of Our Own. Search for tags related to My Little Pony (mlp), Danny Phantom, and Applejack. There might be some creative crossovers there.
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.
Well, in this kind of fanfiction, Danny could be controlled by an ectoplasmic parasite. The parasite latches onto Danny and takes over his actions. His eyes might glow a different color to show he's not in control. His friends would first be confused, then realize something is amiss and start investigating.
There could be a fanfic where Danny and Ember accidentally swap powers. This leads to a series of comical and also dangerous situations. Danny has to figure out how to control Ember's power of influencing people through music while Ember struggles with Danny's more combat - oriented powers. It could be a story full of self - discovery for both of them.
Another possibility is that he's facing some emotional turmoil. Danny has a lot on his plate. He has to keep his identity a secret from his friends and family, deal with school, and fight ghosts. All this stress could be causing him to lose his appetite. He might be too worried or preoccupied to even think about food.
One possible story could be that Danny is facing a new and extremely powerful ghost. He needs help from his friends Tucker and Sam. Maybe they need to find a rare artifact to defeat this ghost. They could start by researching in the local library, looking through old ghost lore books. Tucker uses his tech skills to try and track down any leads on the artifact's location, while Sam uses her knowledge of the occult.
Obviously, the main character would be Danny Phantom himself, but in two different forms or versions. One would be the original Danny Phantom from the canon source, and the other would be a version created by the fanfiction. There might also be his friends like Sam and Tucker who could play important roles in helping the two Dannys understand each other and deal with any issues that arise from their meeting.