His spider - sense would be a very useful power in the MHA universe. Given that many battles in MHA involve sudden attacks and surprises, Spider - Man's ability to sense danger before it happens would give him an edge. He could use this to warn his MHA allies and prevent ambushes. Also, his super strength would make him a formidable force against the powerful villains in the MHA world. He could hold his own against even the strongest quirks, like All - Might's strength - based quirk.
Spider - Man fanfiction often showcases the creativity of the fans. For instance, there are fanfictions that put Spider - Man in crossovers with other superheroes or even in different historical settings. I think it's a great way for fans to express their love for the character and expand on the Spider - Man universe that we know from the comics and movies.
The 'team - up' trope is always popular. Whether it's Spider - Man teaming up with Deku and his friends to take on a powerful villain, or the MHA heroes joining Spider - Man to fight a threat in New York. Also, the 'mentor - mentee' trope can work well. Spider - Man could mentor a young hero in MHA, teaching them about responsibility and using their powers effectively.
One interesting crossover could be having Midoriya from MHA gain Spider - Man's powers. He could use his One For All quirk in combination with the web - slinging ability. Picture him swinging between the skyscrapers of Musutafu while also using his super strength in combat. Another idea is Peter Parker attending UA High. He'd bring his scientific knowledge and web - shooting skills, and would probably befriend characters like Izuku and Bakugo. He could also learn some new combat moves from the hero students there.
Spider - Man would likely be confused at first. He respects the Avengers and can't understand why they are suddenly after him. He might try to talk to them, to explain that he's innocent. For example, he could swing up to Captain America and start pleading his case.
Spider - Man would probably be shocked at first. He looks up to the Avengers and being kidnapped by them would be the last thing he expects. He'd likely try to talk his way out, using his quick wit and charm. He might start by asking why they're doing this and try to convince them that they've made a mistake.
He would be very hurt. He might isolate himself for a while, doubting his own judgment in trusting his friends. Spider - Man might also start to question his identity as a hero. After all, if his friends can turn on him, what does that say about his relationships and his role in the world?
Spider - Man would be very confused. He would feel betrayed because he thought the Avengers were heroes he could trust. He could start by asking them why they are doing this. If they don't give him a satisfactory answer, he might try to escape in a sneaky way, using his spider - like abilities to find a weakness in their capture setup while still trying to reason with them.
Spider - Man would probably be defensive at first. He's used to working alone most of the time, and being interrogated by the Avengers would seem unfair to him. He might crack some jokes to ease the tension, but also firmly state that he's a hero too.
A great crossover idea could be a team - up between Spider - Man and Deku. They could learn from each other's sense of responsibility. Spider - Man has been dealing with the weight of his powers for a long time, and Deku is constantly growing into his role as a hero. They could share their experiences and fight a common villain that threatens both their worlds.