Often, his friends start to search for him. His best friend Ned might use his tech - savvy skills to try and track him down. They might follow some leads that Peter left behind, like a special code or a hidden message.
The Avengers or other superheroes in the Marvel universe could get involved. They realize that Spider - Man is missing and they suspect it has something to do with a bigger threat. So they begin their own investigation, which could lead to all sorts of adventures and battles against new enemies.
The plot may develop with his enemies taking advantage of his weakened state. They might try to attack him while he's in the hospital or at home recovering. On the other hand, his allies, like the Avengers if they exist in that fanfiction world, could come to protect him and help him figure out what caused the collapse in the first place.
Often, his friends in Konoha will start to search for him. They might split into teams and scour the surrounding areas. For example, Sasuke could use his Sharingan to look for any signs of Naruto's departure. Meanwhile, back in Konoha, there could be unrest as the villagers start to worry about the safety of the village without Naruto.
Typically, a Peter Parker identity reveal fanfiction starts with the moment of the reveal itself. It could be due to an accident, like his mask getting ripped off in a big battle. Then, it often shows the immediate reactions of the people around him, like shock from his friends or anger from his enemies. After that, it may explore how Peter has to adapt to this new situation, such as dealing with the media or new threats that come his way because his identity is known.
The story could develop with Steve Rogers being very shocked and then trying to reason with Peter. He might hold back from fighting back because he understands Peter is young and could be acting out of emotion. For example, he could start a conversation to clear the air and find out what's really wrong.
Often, Peter will go off on his own path. He might start to form his own team or work independently to prove himself. For example, he could start taking on smaller villains in his neighborhood to show that he doesn't need Tony's support.
In some fanfictions, Peter could have a sort of out - of - body experience. He might meet some important figures from his past or gain some new insights while his heart is stopped. This could then influence the way he approaches life and heroism once he is revived. And when he is revived, he might come back with new powers or a stronger sense of purpose.
Often, they start with a chance encounter. For example, Peter might save a girl and from there, the interest begins. Then, as the story progresses, more characters get added to the harem through similar situations or shared goals.
In some fanfictions, Harry's disappearance could lead to the discovery of new magical powers or places. Maybe he stumbles upon a hidden magical realm while in hiding. This new place could have its own set of rules and powers. As he tries to figure out how to get back to Hogwarts or deal with the situation that made him disappear in the first place, he has to learn about these new powers and make alliances with the beings in this new realm.
Peter Parker might develop by becoming more of a leader. In the fanfiction, he could step up and take charge in certain situations, guiding the other heroes. This would be a big change from his more inexperienced self in the movies.
His character often becomes more mature. By time traveling during the Civil War, he sees the consequences of the heroes' actions on a larger scale. This makes him more responsible and strategic in his decisions.