Well, one possible plot could be that Xehanort's essence or some form of his power gets transferred into the Harry Potter world. This power could start to corrupt some of the wizarding community, and Harry, with his strong sense of right and wrong, has to trace the source of this new evil. Along the way, he discovers more about Xehanort's past and motives, and has to use his knowledge of both the wizarding world and Xehanort's methods to defeat this new threat. It would be a complex plot that would require a lot of world - building to combine the two very different fictional settings.
One possible plotline could be that Harry has done something extremely dangerous or against the wizarding laws in the fanfic world. Lily, as his mother, feels that she needs to discipline him in a more severe way than just a talking - to. So she resorts to spanking as a last - ditch effort to make him understand the gravity of his actions.
Well, perhaps the Yautja is on a hunt in its own world but gets caught in a magical portal that leads it to Hogwarts. The students are both scared and intrigued. Hermione starts researching about it, trying to find a way to send it back. Meanwhile, the Yautja sees the Death Eaters as worthy prey and starts stalking them. Harry has to convince the Yautja not to go on a full - out killing spree which might endanger innocent lives as well.
A possible plot could be that a Smilodon escapes from a magical menagerie in the Forbidden Forest. Harry and his friends discover it and try to return it safely without getting hurt or getting in trouble with the Hogwarts authorities.
Perhaps Harry could be a wizard - geisha hybrid. He might use his magic to enhance the traditional geisha arts, like creating magical illusions during his performances. He could be in a Hogwarts - like school but also trained in the ways of the geisha, with spells and potions being used in the context of geisha traditions.
Well, one possible plot could be that Orochimaru somehow finds his way into the Harry Potter universe. He might be interested in the unique magic there, like the Elder Wand or the Philosopher's Stone. He could try to use his ninja skills and devious ways to steal these powerful magical items, and Harry and his friends would have to stop him using their own magic.
In this 'harry potter math fanfiction', it might also be that there is a new subject in Hogwarts called 'Magical Math'. The teachers could be magical creatures who are experts in both magic and math. The students would have to learn things like how to use equations to create spells or use geometric shapes to build magical structures. And there could be a big competition where the students use their math skills to win a great prize, like a magical artifact that can enhance their magic power.
A possible plot could be Morgoth's return in a weakened form in the Forbidden Forest. His presence starts to corrupt the magical creatures there. Harry and his friends sense the disturbance and go to investigate. They soon realize it's a much greater threat than they thought and must find a way to either banish Morgoth back to his realm or destroy his essence completely.
Well, perhaps in this fanfiction, Harry Potter uses his magical skills in the context of auditing. He could use spells to detect financial irregularities, like a magical version of auditing software. For example, he might cast a spell that reveals hidden transactions in a company's books.
One possible implication is that it would completely change the perception of Harry's character. He would no longer be seen as the innocent hero but rather a character with a potentially dark and dangerous side. Another implication could be on the relationships in the story. His friends might view him differently and there could be a lot of mistrust. Also, the moral landscape of the story would be altered. Instead of a clear battle between good and evil with Harry on the side of good, it would become more muddled.
One possible plot could be that Harry and Ginny go to a secluded wizarding cottage by the sea. They spend their days exploring the nearby magical creatures and hidden coves. At night, they sit by the fireplace and share stories from their Hogwarts days, strengthening their bond even more.