Another interesting concept is a crossover of the characters' personalities. For example, Sans could befriend Percy and teach him some of his laid - back but observant ways. And Percy could introduce Sans to the world of Greek mythology. They could go on an adventure together in a world that combines the two universes.
One idea could be that Percy and his friends get transported to the Undertale universe. Percy might use his water powers to interact with the magical elements there, like the Echo Flowers. Maybe he has to face off against some of the Undertale monsters using his demigod skills.
One idea could be that Percy ends up in the Underground world of Undertale. He might use his water powers in unique ways against the monsters there. For example, he could create water shields to block attacks from the more aggressive monsters like Undertale's Flowey. Another idea is that Sans could somehow end up in the Camp Half - Blood from Percy Jackson. Sans' laid - back attitude would be a contrast to the usually intense and heroic demigods at the camp.
Another interesting concept is a crossover of the storylines. The prophecy in Percy Jackson could somehow be related to the events in Undertale. For instance, the hero's journey in both worlds might be intertwined, with Percy and Frisk having to work together to save both their universes from a common threat.
One idea could be a fanfiction where Percy and his friends go on a new quest in a modern, urban setting. Instead of the usual mythological locations, they have to deal with monsters hiding in big cities. Another idea is a story that focuses on the relationships between the characters in a more in - depth way, like exploring the friendship between Percy and Grover during their off - quest times. And a third idea could be a time - travel fanfiction, where Percy gets sent back to the time of the ancient Greek heroes and has to interact with them while still holding onto his modern values.
One idea could be to explore Percy's life after he has fully mastered his powers. Maybe he goes on a quest to find a long - lost relative who also has demigod powers. Another could be a story where Percy and his friends have to deal with a new type of monster that is immune to their usual weapons and they have to find a creative way to defeat it.
Perhaps in the fanfiction, Percy could experience a mental collapse. This could be due to all the pressure and trauma he has faced over the years. His friends might have to find a way to bring him back from this dark place, and in the process, we could see deeper relationships develop among them. For example, Annabeth could use her knowledge and their shared history to reach Percy on a different level.
Another concept could be that a powerful ancient evil is affecting both the Percy Jackson universe and Arendelle. Elsa and Percy are the only ones who can sense it at first. They must team up, traveling between their two worlds, to find the source of the evil. Along the way, they learn about each other's powers and cultures, and their combined powers are the key to defeating the evil.
One idea could be a crossover where Harry and Percy meet in a magical realm that combines the wizarding world and the world of Greek gods. They could team up to fight a common enemy, like a dark wizard who has also angered the gods.
One idea could be a fanfiction where a character gets a tattoo of Percy's sword, Riptide. The tattoo could have magical properties in the story, like glowing when danger is near. Another idea is a tattoo of the Camp Half - Blood logo. It could be a symbol of pride for a demigod character in the fanfic, and maybe it was given to them as a mark of their belonging to the camp.
Another interesting concept is a story where Percy Jackson is somehow transported to the Marvel universe. He could use his water - controlling powers in unique ways there. Maybe he'd join forces with Namor, the Sub - Mariner, and they'd have an underwater adventure together, facing off against some underwater threat that only their combined powers could handle.
In Ambrosia Percy Jackson fanfiction, one interesting idea could be new uses of ambrosia. For example, it might be used to heal not just physical wounds but also emotional traumas. Some fanfictions may explore how different characters react to ambrosia in unique ways. Like a new demigod who has never tasted it before might have a very different experience compared to Percy.