One great Aquaman crossover fanfiction is 'Aquaman and the Justice League's Galactic Adventure'. In this story, Aquaman teams up with other Justice League members and they go on an intergalactic mission. It combines the underwater world of Aquaman with the vastness of space in an exciting way. The characters are well - written and it's a thrilling read.
First, you need to have a clear idea of which other universe or character you want to cross Aquaman with. For example, if it's with a character from another DC universe like Batman, think about how their personalities and abilities will interact. Then, create a plot that gives a reason for them to meet. Maybe there's a common threat they need to face.
Perhaps Percy is on a quest related to Poseidon and accidentally crosses paths with Aquaman. They initially have a misunderstanding, thinking the other is a threat. But then they realize they both have a common goal - to protect the seas. So they team up to stop a group of evil sea witches who are polluting the ocean and causing chaos among the sea life. Aquaman uses his trident and connection to the ocean's life, while Percy uses his sword and his wits to outsmart the witches.
One possible plot could be that Aquaman somehow finds himself in the wizarding world of Harry Potter. Maybe a magical spell gone wrong transports him there. He could use his unique underwater abilities to help the Hogwarts students in a task related to the Black Lake, like retrieving a powerful magical artifact that has sunk to the bottom.
At first, they might be cautious around each other. Aquaman, being the king of Atlantis, would be wary of this strange demigod from the surface world. Percy, on the other hand, would be in awe of Aquaman's power and the strange underwater world. But as they face challenges together, like fighting off some menacing sea creatures or stopping a villain who wants to control the ocean, they would start to respect and rely on each other. Percy might crack some jokes to lighten the mood, which Aquaman might find strange at first but then start to appreciate as a sign of Percy's courage.
Well, in a Harry Potter and Aquaman crossover fanfiction, we might see Aquaman's Atlantean magic interacting with Hogwarts' magic. For instance, the Sorting Hat might have a hard time sorting an Atlantean student brought by Aquaman. Also, Harry and his friends could go on an adventure to Atlantis with Aquaman as their guide, exploring the underwater world full of strange creatures and ancient magic.
Aquaman's ability to control the sea could be used to create massive water - based defenses around Hogwarts. In return, Harry could use magic to give Aquaman the ability to breathe air indefinitely when he's on land for extended periods. Their powers could also combine in a more offensive way. For instance, Harry could use a levitation spell on Aquaman while he's in the water, allowing Aquaman to attack enemies from above the water surface with his enhanced speed and strength.
It could be Aquaman. He is so different from the wizards in the Harry Potter universe. His fish - like abilities and his role as a king would make for some great interactions with the Hogwarts students and professors. He could teach them about the ocean and its secrets, while also being amazed by the magic of wands and potions.
One possible plot could be that Aquaman discovers a magical portal in the depths of the ocean that leads to the wizarding world of Harry Potter. He then teams up with Harry to fight a new threat that is endangering both the underwater kingdom and Hogwarts. Maybe it's a dark magic - using sea creature that has gone berserk.
It could be a wizard who has gone mad with power and wants to control both the wizarding world and the underwater realm. He discovers a way to use dark magic to manipulate sea creatures and cause destruction in Aquaman's kingdom. He then sets his sights on Hogwarts as well, seeing it as another source of power.