His personality might become more in touch with his emotions. As a girl, Peter could be more empathetic and sensitive. He might also be more cautious in some situations, as society often treats girls differently. For example, he might not be as quick to jump into a fight without thinking about the consequences more carefully.
Loki is known for his mischievous nature. In this fanfiction, he could bring out a more playful side in Peter. Peter might start to use his powers in more creative and unexpected ways, like using his web - slinging not just for fighting and swinging around, but also for creating elaborate pranks, inspired by Loki. Also, Loki's manipulative side could either make Peter more distrustful of others or teach him how to spot manipulation better, depending on how their relationship develops.
Peter could get a dog. A loyal dog would be a great companion for him, following him around during his daily life and even being a sort of sidekick. It could sense danger and bark to alert Peter when something was wrong.
In these fanfictions, it can change the pacing of the story. For example, Peter might have to stop and catch his breath during a fight, which gives a different rhythm to the action scenes. Also, it can affect his relationships. His friends and family might be more protective or worried about him. And it can also be a source of character growth as he learns to overcome this obstacle while still being Spider - Man.
It could be a vengeful criminal that Spider - Man has put away in the past. This criminal has spent years in prison plotting his revenge and finally gets the chance when Peter is vulnerable. Maybe he manages to ambush Peter in an alleyway while he's on his way home from school or work.
One plot development could be the reaction of the Avengers or other superheroes to Peter's transformation. They might be initially confused or even skeptical about whether it's really Peter. And Peter, as a girl, would have to prove herself all over again in the superhero community. There could also be a plot where she discovers new powers or abilities that come with her new form. This could lead to her being more of an enigma in the superhero world and having to figure out how to control these new powers while still maintaining her identity as Peter Parker at heart.
His personality might become more reclusive. Since spiders are often solitary creatures, Peter could start to withdraw from his social circle. He might be less likely to engage in his usual banter with his friends at school. Instead, he'd be more focused on his new - found spider instincts, like finding quiet places to rest or being more aware of his surroundings in a way that makes him seem aloof to others.
One idea could be that Peter Parker gets a prosthetic after a particularly dangerous battle with a villain. Maybe his leg is severely injured and he has to adapt to the new prosthetic while still maintaining his superhero duties. He could struggle at first with the balance and movement, but with his determination, he eventually masters it and even modifies the prosthetic to have some special features like enhanced jumping ability.
Definitely Aunt May. She would be super worried about baby Peter and would do everything she could to take care of him. She might even call in some old friends or neighbors to help out.
One interesting plot could be that the other Avengers have to take care of baby Peter. They struggle with things like changing diapers and feeding him, all while trying to figure out how to turn him back. It would be really funny to see tough heroes like Thor or Iron Man being clueless about baby care.
Peter might be more reserved and calculating like Natasha. Instead of his usual impulsive self as Spider - Man, he would think things through more carefully. His sense of humor might also be a bit darker, influenced by Natasha's past and her own brand of dry humor.