Perhaps in this fanfiction, a villain has somehow transferred Percy's power of hypnosis to himself and uses it on Annabeth to get information from her. Percy then has to race against time to break the hypnosis and save Annabeth, all while facing various challenges and obstacles set by the villain.
Maybe the main antagonist is an old enemy of Percy's who has learned about his newfound ability to hypnotize (even if it was accidental). This enemy decides to use Annabeth as a pawn by hypnotizing her, hoping to lure Percy into a trap and defeat him once and for all.
One possible plotline could be that a new villain, who has powers of hypnosis, targets Annabeth because of her strategic mind. The villain wants to use her knowledge of Camp Half - Blood and the demigod world to their advantage. Percy and the others then have to figure out how to break the hypnosis and stop the villain before it's too late.
I'm not sure specifically about Annabeth being hypnotized fanfics in Percy Jackson. But you can start by looking on fanfiction.net or Archive of Our Own. Search for 'Percy Jackson Annabeth hypnotized' and you might find some interesting stories. Just be sure to read the tags and summaries carefully to make sure it's what you're looking for.
In a large number of Percy and Annabeth fanfictions, they are indeed presented as soulmates. Their shared adventures, the way they understand each other without many words, and the deep loyalty they have for one another all contribute to this perception. Fanfiction authors often build on their existing relationship from the original works and enhance it to the level of soulmates. They might show it through things like Percy being able to sense Annabeth's distress from afar, or Annabeth always knowing exactly what Percy needs in difficult situations. This soulmate - like relationship makes for very engaging and heart - warming stories in the fanfiction realm.
It could be that Annabeth has a misunderstanding about Percy. She might think he's a threat to her position or status at the camp, so she bullies him to try and keep him in check.
It could be Chiron, the centaur. He's always keeping an eye on the campers and would likely be concerned if he caught them up to something. He might give them a stern talking - to and some extra chores as punishment.
Percy might be a bit flustered and embarrassed. He's protective of his relationship with Annabeth, so having Magnus walk in might make him feel like their privacy has been invaded. He could quickly try to shield Annabeth or just look really shocked.
Their shared experiences play a big role. They've been through so much together, like countless battles and adventures. Percy has seen Annabeth in tough situations and he knows how strong she is, but also how vulnerable. So he feels the need to protect her. For instance, they might have had a close call in a previous adventure where Annabeth was nearly killed, and that memory makes Percy extra vigilant.
Their relationship is likely to be complex. They are friends and comrades who have fought side by side many times. So, there's a strong bond of loyalty between them.