In such a fanfic, Harry might experience extreme pain and weakness. His friends would likely be in a panic. Hermione would probably immediately start looking for antidotes in the library or with her vast knowledge of potions. Ron would be by Harry's side, trying to keep him conscious and reassuring him.
In a 'Harry Potter is poisoned' fanfic, it depends on who poisoned him. If it was a jealous student, perhaps they didn't realize the full extent of what they were doing. Harry's symptoms could include vomiting, dizziness, and a paling of his skin. His friends would be desperate to save him. They might seek help from the Forbidden Forest creatures if they thought they could find a cure there. And the whole wizarding world might be on edge, fearing that Voldemort was behind it all.
If Harry Potter gets poisoned in fanfiction, it could lead to some really interesting plot twists. His magical powers might be affected. He could start having strange visions or lose some of his abilities temporarily. Dumbledore or other teachers might get involved in a big way to figure out who poisoned him. And the whole Hogwarts community could be in an uproar, with students trying to find out the truth and protect Harry from any further harm.
He might be quite amused. Fanfics often contain different interpretations of the characters and the wizarding world. He could find some creative ideas in them that he never thought of before, like unique magical spells or new backstories for his friends.
Well, he could bring his magic skills to the team. Maybe he could use spells to enhance the Avengers' weapons or defenses. For example, he could put a protection charm on Iron Man's suit to make it even more resistant to attacks.
Well, he might start collecting Pokemon cards instead of magic ones. He could try to use spells to catch Pokemon, which would be really interesting.
Well, in a 'Harry Potter adopted by Delacours' fanfic, it could be really interesting. Harry would be part of a family that has a different set of values and customs. The Delacours might train him in unique ways of magic that are more in line with Beauxbatons. He could get to know the Veela heritage better, and perhaps it would give him some advantages in his magical abilities. Also, there could be new storylines around his interactions with the Delacour family members and how they deal with the fame and danger associated with Harry.
Well, it would be a really dark take. Harry would probably be constantly in a state of near - despair. Since Dementors are soul - sucking creatures, he might have a hard time forming normal relationships. His view of the wizarding world would be very different from the original story. He might see it as a place full of threats and darkness rather than a place with some good in it. And his Patronus, if he could even produce one, would be very weak or have an unusual form.
In a fanfic where Harry Potter gets a lawyer, it could lead to some really interesting plot developments. Maybe the lawyer helps him deal with the legal mess left by the Ministry of Magic's previous actions against him. For example, clearing his name regarding the false accusations of being a dark wizard or dealing with property rights issues related to his family's estate at Godric's Hollow.
Well, he'd probably become super powerful. The symbiote could enhance his magic skills and give him some cool physical abilities like super strength and agility. Maybe he could use it to fight the Dark Arts in a whole new way.
If Harry Potter moves to America in a fanfic, he'd likely encounter new friends and foes. American wizards might have different attitudes towards his fame. Some might be in awe, while others might be more skeptical. He could also get involved in American magical politics, which could be very different from the British Ministry of Magic's operations. And his magic skills might be seen in a new light, as the American magical world may value different types of magic.
In such a fanfic, Harry might be tortured for information about the Order of the Phoenix. Voldemort could try to turn Harry to the dark side, using his powerful magic to break Harry's will.