I'm not sure specifically as there could be many interpretations. It might be a dark and fictional scenario where Scott has a motive to kill Peter within the context of a fan - created story.
Peter could use his agility. Since he's super - agile, he can dodge Thanos' attacks easily. Then, when Thanos is off - guard, Peter can strike. For instance, he can web up Thanos' hands so he can't use the Infinity Gauntlet properly.
Yes, there might be such a fanfiction out there. Fanfiction often explores dark and alternative storylines. However, it can be quite a controversial and dark concept as Tony and Peter have a mentor - mentee relationship in the mainstream Marvel stories.
In the fanfiction, there could be a range of consequences. On one hand, he could be seen as a hero by his fellow students. They might admire his bravery and his ability to take on a dangerous troll. However, the teachers may be more cautious. If Harry used excessive force or magic that was not in line with the school's code of conduct, he could be given detention or even face a disciplinary hearing. Also, depending on how the troll was killed, there could be some magical fallout. For example, if he used a very dark spell, it could have an effect on his own magical core or his relationship with magic in general. Moreover, the death of the troll might also attract the attention of other dark creatures or forces that were somehow related to the troll, putting Harry in further danger.
One consequence could be that he becomes a hero among his peers. Everyone in Hogwarts might look up to him even more. The other students could see him as a real dragon - slayer, which gives him more popularity and respect.
One consequence could be that Peter Quill Parker becomes a hero. People all over the universe might look up to him. But he may also face some jealousy or envy from other powerful beings.
One possible plot twist could be that Peter uses his intelligence rather than just his powers to defeat Thanos. Maybe he discovers a weakness in Thanos' armor or a flaw in his plan that no one else has noticed. For example, he could find out that Thanos' Infinity Gauntlet has a time - limited recharge period for its powerful snaps, and he uses this knowledge to his advantage at a crucial moment.
One possible plot could be that Peter Parker discovers a new power within himself that gives him the edge to take on Thanos. Maybe it's a power related to the Time Stone that he manages to manipulate in a way that Thanos can't counter. He could use this power to outwit Thanos in a battle and finally deliver the killing blow.
After Harry kills Voldemort in the graveyard in the fanfiction, the magical balance might shift. With Voldemort gone, some of the dark magic that was prevalent might start to fade away. The Hogwarts School of Witchcraft and Wizardry could see a new golden age. New spells and magical theories might be explored as the fear of Voldemort no longer holds back the wizarding scholars. Harry himself might start to travel around the world to spread the news of Voldemort's defeat and also to learn more about different types of magic. His friends would also have new opportunities, like Hermione might be able to further her studies without the constant threat of Voldemort and Ron could finally relax and enjoy a more peaceful life at the Burrow.
One consequence could be that he becomes a hero among the wizarding community. People start to look at him with even more admiration and respect. His reputation as a powerful wizard grows even stronger.