A possible plot could be that the magic in the Harry Potter world has an unexpected effect on Bruce Banner. When he enters Hogwarts, the magic starts to interact with the gamma - radiation in his body. This causes his Hulk form to change. Instead of being a big, green brute, the Hulk becomes a magical - enhanced version. He has new powers related to magic, like being able to shoot magical energy blasts. Harry Potter and his friends initially see the Hulk as a threat but then realize they can use his new powers to fight against the dark wizards who are trying to take over Hogwarts.
One idea could be that Bruce Banner is somehow transported to the wizarding world of Harry Potter. Maybe he arrives during a time of great danger, like when Voldemort is at his most powerful. Bruce's scientific knowledge could be combined with magic in unexpected ways. For example, his understanding of gamma radiation might interact with some of the more dangerous magical spells or potions. He could also form an unlikely friendship with Harry Potter. Harry could teach him about magic, while Bruce could show Harry some of the scientific concepts from his world.
Maybe Fem Harry Potter is on a quest to find a magical object that has found its way into the Marvel world. Bruce Banner, in his Hulk form, initially scares her but then they realize they can help each other. The Hulk's strength could be useful in protecting Harry from physical threats while she uses her magic to protect Banner from magical ones.
Perhaps Bruce Banner adopts Harry Potter after the events at Hogwarts. He takes Harry to the world of science, showing him things like advanced laboratories and scientific research. Harry, in turn, shows Bruce the wonders of magic. Their bond grows as they learn from each other, and together they face new threats that combine elements of both the magical and scientific worlds.
One interesting concept could be a crossover where the magic of the Harry Potter world interacts with Bruce Banner's scientific knowledge. Maybe Banner could be intrigued by the potions in the wizarding world and try to analyze them with his scientific mind. Another concept might be a situation where the Hulk's strength is pitted against the powerful magic spells of Harry Potter characters.
One possible plot could be that they are brought together to solve a mystery that combines magic and science. Maybe a powerful artifact has been found that is both magically and scientifically complex, and their combined knowledge is needed to figure out how to handle it safely.
Another plot could be that Bruce Banner is doing some research on a new form of energy and it somehow links to Harry's magic. Harry is brought in to help understand this strange new energy which has properties similar to magic. In the process, they learn from each other's worlds and develop a friendship while trying to keep this discovery from falling into the wrong hands.
I really liked a fanfic where fem Harry Potter accidentally travels to Bruce Banner's world. It shows how she tries to adapt to this new world full of science and technology, which is so different from the magical world she's used to. And Bruce Banner is intrigued by her magic. It's a great exploration of two very different characters coming together.
In fanfiction, Bruce Banner could save Harry Potter through his scientific knowledge as well as the Hulk's powers. Maybe there's a situation where a magical curse is spreading uncontrollably. Bruce, in his normal state, could analyze the curse using his scientific expertise and figure out a way to stop it. And if there are any physical manifestations of the curse that need to be dealt with, the Hulk could step in and use his strength to destroy or contain them. This would show a great combination of the scientific and magical elements in the story.
I think the interaction between Bruce Banner and Hagrid would be fascinating. Hagrid is used to dealing with all kinds of strange creatures, but the Hulk would be something entirely new. He would probably be both scared and intrigued. Also, Bruce and Snape could have an interesting dynamic. Snape's brooding and often misunderstood nature might resonate with Bruce. Snape could be interested in the scientific aspects of Bruce's transformation, while Bruce might be able to see through Snape's tough exterior to the good in him.
If they meet, Bruce Banner might be really intrigued by the magic in Harry's world. He could see it as a new form of science. And Harry could be fascinated by Bruce's scientific knowledge. They might exchange ideas, with Harry showing Bruce how magic can do things like teleportation, and Bruce explaining some scientific concepts to Harry, like how gamma radiation works.
Harry is brave and determined. Bruce is intelligent but often hesitant due to his fear of the Hulk. Harry might encourage Bruce to be more confident. He could say things like 'You have so much power within you, don't be afraid to use it for good.'