Maybe it's an emergency call from his family. In that case, he would have to explain the situation to the teacher quickly. If the teacher is understanding, he might be allowed to step out of the class to deal with the emergency.
It could also be a call from a friend playing a prank. Peter might be really embarrassed when he realizes it. He'll have to face the stares of his classmates and the scolding of the teacher for disrupting the class.
Well, he might get in trouble with the teacher. Teachers usually don't like students getting phone calls during class. So, the teacher could take his phone away and give him a detention.
Well, it depends on who's calling. If it's Tony Stark, for example, Peter would be super excited and might not be able to hide it. He could try to come up with some lame excuse to leave the class, like saying he has a stomachache. But the teacher might not believe him. And his classmates would be curious about who's on the other end of the call.
Perhaps it's his best friend who has some juicy gossip to share. But it's really bad timing as he's in class. His friend might not be aware of his class schedule.
Maybe Percy gets in trouble for answering the call during class. It could disrupt the whole class and the teacher might scold him.
Well, in the fanfiction, perhaps it's a call from an old friend who needs his help. Dante might then gear up and set off on a new adventure to assist his friend.
He could be using his phone to track a villain's movements. Maybe he installed some special app on his phone that can detect unusual energy signatures. So while the teacher is droning on about history or math, Peter is secretly following the path of a super - villain who is on the loose in the city.
Maybe he'll get in trouble with the teacher. In a classroom, getting a call is usually not allowed. The teacher might scold him or confiscate his phone.
One possibility is that Tony calls Peter to discuss an upcoming science project. Maybe they need to work together and Tony wants to plan out their tasks in class so they can start right away after school.
One possibility is that Peter gets really flustered. He might be in the middle of paying attention to the teacher when Deadpool calls, and his first reaction could be to try and hush Deadpool. Since Peter is often portrayed as a responsible student, this unexpected call could throw him off his game in class.
There's also a chance that it could be a new superhero or villain. Maybe a new hero wants to team up with Spider - Man or a villain is taunting him, starting a new plot in the fanfiction world. This would create an exciting situation for Peter to deal with while trying not to blow his cover in class.
Maybe Percy gets in trouble with the teacher. Teachers usually don't like phones going off during class.