Fred could use his knowledge of the Weasley family's magic tricks and inventions. He might have some secret gadget or spell that can break through the barriers or spells that are being used to torture Hermione.
Perhaps by having strong friendships come into play. If the story shows that Fred or other friends are desperately trying to save Hermione, it gives the reader hope. Like, Fred could be rallying the other Weasleys and Hogwarts students to find a way to rescue her from the torturous situation.
One possible fanfiction could be where Fred and Hermione discover their Animagus forms together. Maybe they transform in the Forbidden Forest and have to rely on each other to get back to Hogwarts safely. Their forms could be something that represents their personalities, like Fred could be a fox, known for its cleverness and playfulness, and Hermione could be an owl, symbolizing wisdom.
I'm not a big fan of such dark fanfictions, but you could try looking on fanfiction.net. They have a large collection of Harry Potter fanfictions, and you might be able to find one with that plot there.
Well, in some versions, Fred might use his quick-witted magic skills. He could cast a distraction spell to draw Bellatrix's attention away from Hermione. Maybe a spell that creates multiple illusions of himself, confusing Bellatrix long enough for him to grab Hermione and disapparate them to safety.
Hermione herself could be more vigilant. If she noticed any signs of danger or people acting strangely around her, she could take precautions. She could use her own intelligence and magic to create defenses. For instance, she could set up a spell that alerts her when someone with malicious intent is near, and then she could either escape or fight back.
One reason could be that they played a particularly mischievous prank on her that went too far. For example, if they made her late for an important exam or meeting with a professor by using one of their wild magical inventions. Hermione, being a stickler for rules and academic achievement, might lose her temper and hex them in retaliation.
I'm not entirely sure if there is a specific 'Fred terrified of Hermione' fanfiction. It depends on the creativity of the fanfic writers in the fandom. Some writers might explore this unique dynamic for comedic effect, while others might use it to create a more complex and unusual plot. However, the best way to know is to search for it as I mentioned before.
Well, it's a wild fanfiction concept. Fanfic writers might play with the idea by having some sort of magical mix - up or a different relationship path for Hermione. Maybe there's a spell gone wrong that leads to this unexpected pregnancy. But it would surely be a huge departure from the original story's themes and relationships.
I'm not sure if there is a specific fanfiction exactly with that title. However, in the vast world of fanfiction, there could be many stories exploring different relationships and scenarios. You can try searching on popular fanfiction websites like FanFiction.net or Archive of Our Own using relevant keywords to see if such a story exists.