Well, perhaps the plot could be about Fred and George getting into some sort of magical mischief together while George is on Fred's back. Maybe they're trying to escape from Filch in Hogwarts and they have to use some unique spells to get away, all while George is piggybacking on Fred.
It could be that they are on a quest to find a hidden magical item in the Forbidden Forest. George is on Fred's back because he's injured his leg. As they journey through the forest, they encounter various magical creatures and have to use their wits and magic to avoid danger and finally reach the item.
The fanfic might be about a friendly competition between them. George is on Fred's back and they are racing against other Hogwarts students. Along the way, they face obstacles like magical traps set by the other students. But they use their Weasley twins' charm and cleverness to overcome them and win the race.
One possible plot could be that Fred and George, being their mischievous selves, get involved in some sort of magical prank that goes awry. And perhaps Potter, Harry Potter I assume, gets accidentally caught up in it. For example, they could be testing a new product in their joke shop and it causes chaos in Hogwarts, with Potter having to help them fix the mess to avoid getting them all in serious trouble.
It could be Draco Malfoy. He's always causing trouble for Potter and the Weasley twins would surely not be on his good side either. So he could try to foil their plans and cause problems for them throughout the fanfic.
This fanfic would be different because it focuses on the physical interaction of Fred giving George a piggyback. Most Potter fanfics might be more about battles or romances. Here, it could be a story about brotherly love and support shown in this unique way.
It could be part of a magical experiment gone wrong. Fred and George are working on a new spell that has something to do with making people feel extreme sensations. By accident, when they test it on Harry, it turns into a tickling sensation. So they have to figure out how to reverse the spell while Harry is being tickled non - stop and is both laughing and begging them to stop.
Friendship is a very common theme. Since Fred and George are known for their close bond, and when you add Potter into the mix, it often explores how their friendship extends to include him. Another theme could be adventure, with the three of them getting into all sorts of magical escapades.
One possible plot could be that there is a magical accident which creates a marriage bond between the three. At first, they are all confused and perhaps a bit resistant. Fred and George might be worried about how this will affect their twin dynamic and their business at Weasley's Wizard Wheezes. Hermione, on the other hand, is likely concerned about how this will impact her studies and her plans for the wizarding world's betterment. But as time goes on, they start to discover new things about each other. They realize that they can support each other in ways they hadn't expected. Fred and George's sense of humor helps Hermione loosen up a bit, and her intelligence helps them with the more serious aspects of their business and magical research. Eventually, they learn to accept the bond and build a unique relationship together.
Yes, there are likely fanfics out there with such a scenario. Fanfic writers often come up with creative and unique plotlines. You can start by looking on popular fanfic websites like Archive of Our Own or Fanfiction.net. Just be aware that the quality and nature of these fanfics can vary widely.
Innovation in magic is also a common theme. Since they are inventors in the original books, fanfics usually depict them creating new magical items or spells. They might be working on something that could change the way magic is used at Hogwarts or even in the wizarding world as a whole.
One great 'Harry Potter Fred and George fanfic' is 'The Prankster's Legacy'. It shows their post - Hogwarts adventures full of new pranks and magical inventions. Another is 'Fred and George: The Twin Tales' which delves into their childhood and how they came up with all those amazing ideas. And there's 'The Weasley Wonders' that focuses on their relationship with the rest of the Weasley family while still highlighting their unique twin bond.
Fred could be sick because he was experimenting with a new type of potion and something went wrong. His illness could make him lose his memory bit by bit. George is desperate to find a way to reverse it. He asks Snape for help, but Snape is reluctant at first. However, when he realizes it's a serious matter, he starts to look into it. As Fred's memory fades, he forgets about all the pranks he's done, and his relationships with his friends and family. It's a race against time to find a cure before he forgets everything and everyone he loves.