A great plot could be that Peter Parker's 'acting like a spider' behavior is caused by some sort of magical or scientific mishap. Maybe he gets exposed to a new type of radiation or a spell goes wrong. As a result, he not only acts like a spider but also starts to develop some spider - like instincts on a deeper level. He might have an irresistible urge to climb walls all the time, even when it's not necessary for crime - fighting. His friends would be very confused at first, but as they learn more about what's going on, they help him find a way to reverse the effects while also having some wild adventures along the way.
Well, in this fanfiction, perhaps Peter Parker begins to mimic a spider's hunting behavior. Instead of just using his powers to fight crime in the traditional way, he starts to stalk his enemies from the shadows, waiting patiently for the perfect moment to strike. He could also use his webs to create elaborate traps, like a spider does for its prey. This would give a whole new and interesting dynamic to his crime - fighting adventures.
Peter Parker could be developed by emphasizing his new - found spider - like curiosity. He might start exploring the city in a different way, noticing small details and hidden corners that he previously overlooked. This could lead to him discovering new threats or helping people in unexpected ways.
One possible plot could be that Peter Parker's transformation into a spider is a permanent one. He has to deal with not just his regular superhero duties but also the new challenges of being part - spider all the time. Maybe he has to learn new ways to communicate with other spiders to gain some special knowledge or power.
Maybe in this fanfiction, Peter's mutation into Spider is caused by some new and experimental Oscorp technology. The process is different from how he originally got his powers. As he mutates, he starts to lose some of his human memories and instincts, becoming more primal like a spider. His relationship with Aunt May would become very strained as she tries to understand what's happening to her nephew. Meanwhile, he has to face off against new enemies that are specifically attracted to his new spider - like form, thinking he's some kind of new prey or threat in the city.
Maybe in the fanfiction, after getting married, they decide to create a new superhero team together. But they face difficulties in recruiting members as some people are skeptical about a married couple leading a team. This could lead to a series of adventures where they prove themselves as capable leaders and build a strong team.
One interesting plot idea could be Peter trying to balance his high school life with new, more dangerous threats in Queens that are not related to the big - name villains. Maybe a group of tech - savvy thieves are using stolen Stark tech in creative ways, and Peter has to outwit them without revealing his identity to his classmates. Another idea is exploring Peter's relationship with his teachers in a more in - depth way. For example, a teacher suspects that Peter is up to something unusual and starts to investigate, putting Peter in a tricky situation.
One plot idea could be Peter dealing with only half of his spider - powers. For example, he might be able to climb walls on one side of his body but not the other. This could lead to some really comical yet challenging situations as he tries to adapt.
The field trip could be to a historical site. Peter senses that there are some ancient artifacts with strange powers hidden there. A group of thieves, who are also aware of the powers, are planning to steal them. Peter has to figure out how to stop them. He could use his knowledge of history (from all his studying) to outwit the thieves. For example, he might know of a secret passage or a trap that he can use to his advantage to protect the artifacts and keep his classmates safe at the same time.
In the 'naruto acts like a cat fanfiction', a plot could be that Naruto befriends a group of stray cats in the village. They teach him their ways, and he in turn, protects them from the meaner villagers. As he acts more like a cat, he starts to understand their language, sort of like a telepathic connection. This connection helps him gather intelligence from all the places the cats can go, which he then uses in his ninja duties. This would be an interesting way to show Naruto's kind heart and his ability to adapt to new situations.
Some fanfictions might take Peter Parker to different universes. He could end up in a world where there are no other superheroes and he has to figure out how to protect this new place all by himself. This would test his skills and resourcefulness even more.
One interesting storyline could be Peter and Gwen teaming up against a new super - villain in their city. They could combine their unique powers and skills to outwit the bad guy. For example, Peter's spider - sense and web - slinging abilities along with Gwen's acrobatic skills and her own version of web - shooting.