Another option is that it's some new, unknown villains in the fanfiction world. They might have some vendetta against Hermione specifically or against Hogwarts in general, and forcing her under the desk is just the start of their evil plan.
It could be the Slytherins. They are often portrayed as the antagonists in the Harry Potter series. Maybe they're jealous of Hermione's intelligence and want to embarrass her by forcing her under the desk.
In this fanfiction, it could also be that Hermione is forced under the desk as part of a mystery. There could be some hidden secrets or clues under the desk that she needs to discover, but she's being forced to stay there against her will at first. As she investigates, she uncovers something that has far - reaching implications for the wizarding world.
There could be a lot of things like old papers, a lost pen, or some forgotten books.
Perhaps there could be a stack of old, hand - written notes. These notes might contain his personal thoughts on magic, or his memories related to certain spells and potions. Snape is a very private person in the original stories, so these notes could be full of secrets. For example, they could be about his past relationships or his early experiments with magic that he doesn't want others to know about.
Obviously, Harry Potter would be one of the main characters. He's the one who is likely to be under Snape's desk for some reason. And of course, Snape himself. His desk is the central location, so he has to be involved. Also, Hermione might be there. She often helps Harry out, and if Harry gets into trouble under Snape's desk, she could be the one to figure out a solution.
I'm not sure specifically which ones are the most popular for this rather unusual scenario. Fanfiction varies greatly in popularity and availability. However, you can start by looking on major fanfiction platforms like Fanfiction.net or Archive of Our Own. Search for the exact phrase 'Harry Potter Forced Under the Desk' and browse through the results to find ones that seem interesting to you.
It's possible to find a stack of papers. These could be ungraded assignments, old lesson plans, or notes from previous classes. There might also be a small wastebasket under the desk for the teacher to throw away any scraps of paper or used tissues during the day.
I'm sorry, but this topic involves inappropriate and unethical content, so I can't provide relevant fanfictions.
When writing this fanfiction, you need to stay true to the original Harry Potter universe in terms of the rules of magic, the personalities of the characters, etc. For example, Harry is brave but also impulsive at times. You can start with a strong opening that immediately grabs the reader's attention, like a sudden chaos that leads to Harry being forced under the desk. Then, build the plot gradually, with some twists and turns. Maybe the desk is not an ordinary desk but has some secret magical powers. As you write, use vivid descriptions to make the story come alive, like describing the dusty underside of the desk and Harry's feelings of confinement.
It could be Orochimaru. He might be after some valuable information that Sakura has and she has to hide under the desk to avoid him. The 'pop' could be one of his experimental creatures suddenly showing up.
It could be Harry Potter. He's often in the thick of things in Hogwarts, and he might be the one who tells Miss Granger to get under the desk. Maybe he's noticed something strange and dangerous approaching, and his first instinct is to protect her.