There could be. Fanfiction writers are very creative and love to combine different well - known characters. Since Percy Jackson has his own set of powers and the Ghost Rider has his very distinct abilities, a fanfiction where Percy is the Ghost Rider would be a really cool concept. It might explore how Percy would handle the power of the Ghost Rider, how it would interact with his demigod nature, and what new adventures he could have. So, it's very likely that someone has written such a fanfiction.
One common theme is identity. As a ghost, Percy often has to re - evaluate who he is. Another theme is isolation. Since he's a ghost, he may feel cut off from the living world. And then there's the theme of unfinished business. Usually, Percy has something he needs to do or resolve even in his ghostly form.
In a 'Percy Jackson is the Ghost Rider' fanfiction, it would start with Percy getting the Ghost Rider's powers in some unexpected way. Maybe he stumbles upon an ancient artifact that binds the two powers together. With the Ghost Rider's powers, he would have enhanced strength, the ability to see the sins of others, and of course, the iconic flaming skull. Percy would use these powers to protect not only the demigod world but also the normal human world from the threats that the Ghost Rider is known to combat. His relationship with his friends would change as they try to understand his new powers. Some might be scared, while others would be eager to help him master them. And Percy would have to figure out how to balance his two identities, the demigod son of Poseidon and the Ghost Rider, all while facing new and dangerous enemies that are attracted to his unique combination of powers.
There's a fanfiction titled 'Percy, the Ghostly Protector'. In this story, Percy becomes a ghost and decides to protect his loved ones from various threats that they can't see. It's full of suspense and heartwarming moments as he tries to communicate with them in his ghostly form. Well, I also found 'Ghostly Percy: A New Beginning' which shows Percy's journey as a ghost to find a new purpose in his spectral existence.
Well, he'd probably be an extremely powerful and unique Ghost Rider. His skills as a demigod, like his quick reflexes and strategic thinking, would blend with the Ghost Rider's powers. He might use his water - based powers in new ways, like creating steam from the hellfire of the Ghost Rider. And his loyalty to his friends would likely make him a Ghost Rider who protects the innocent in a more personal way.
Ghost Rider would likely have the upper hand in a straight - up fight. His powers come from a demonic source which gives him incredible strength and the ability to dish out some serious punishment with his hellfire chain. Percy, while very strong, mainly relies on his sword and water powers. But if Percy could use his wits and the environment to his advantage, he might be able to hold his own for a while. For example, if they were near a large body of water like an ocean, Percy could create huge waves to try and put out Ghost Rider's hellfire or knock him off balance.
One idea could be that Percy Jackson is somehow transported to the world where Ghost Rider exists. He has to team up with Ghost Rider to fight a common enemy that is threatening both their realms, like a powerful demon that can manipulate water (to challenge Percy) and fire (to challenge Ghost Rider).
I don't know for sure as I haven't read this particular fanfiction, but usually in fanfiction, Percy could be a character from a popular book, movie or TV series.
I'm not sure who Percy specifically is without reading the fanfiction. It could be an original character created by the author, or perhaps a reimagined version of a known character from a particular franchise that the fanfiction is based on.