The potion mishap could bring them closer. If they have to work together to fix the mess caused by the wrong potion, they might start to understand each other better. For example, they could learn about each other's strengths and weaknesses during the process of finding a solution.
One possible scenario in this fanfic could be that Harry and Blaise are working on a difficult potion in Potions class. Maybe they accidentally add the wrong ingredient due to a misunderstanding or a distraction. This could lead to a potion that has unexpected effects, like making them swap voices or even temporarily change their physical appearances.
In a Harry Potter polyjuice potion mishap fanfiction, the person who drinks the potion wrongly might start to exhibit the wrong personality traits. Let's say they were trying to transform into Hermione but due to the mishap, they start acting like Draco Malfoy instead. This would cause chaos as they would be doing things completely out of character for the person they were supposed to be imitating. They might start bullying other students or being mean to their friends, creating a lot of drama and confusion in the wizarding world.
A jealous wizard or witch from the Order of the Phoenix could be the antagonist. They might be envious of Tonks' relationship with Harry or her special abilities. So, when the potion mishap occurs, they try to make the situation worse for her, hoping to get her removed from the Order or at least lose her status among the members.
Ron could be the main character in a Harry Potter polyjuice potion mishap fanfiction. Ron is known for his sometimes hasty decisions. He might be so eager to prove himself or get involved in some secret mission that he doesn't follow the potion - making instructions properly. This could lead to a mishap where he transforms into an unexpected person, and then has to navigate through the wizarding world in this new form, trying to hide his identity from his friends and family while also trying to reverse the effects of the potion.
One possible plot could be that Tonks accidentally creates a potion that makes her swap appearances with Harry. This would lead to a series of comical and confusing situations. For example, Tonks (in Harry's body) has to deal with Harry's friends not realizing it's her, and she has to figure out how to reverse the effect while also not getting Harry into trouble at Hogwarts. Meanwhile, Harry (in Tonks' body) has to navigate the world of the Order of the Phoenix and deal with Tonks' responsibilities.
He might be suspicious at first. Given their different houses and the general tensions between Slytherin and Gryffindor, Harry would be cautious about Blaise's motives.
Well, it could be about a character in the Harry Potter world who has a DNA mishap due to some dark magic experiment. Maybe they start developing strange powers or characteristics that are not normal in the wizarding world. For example, they could have the ability to communicate with animals in a different way than normal Animagi. This would lead to all sorts of adventures as they try to figure out what happened and how to reverse it, while also dealing with the reactions of their friends and foes in Hogwarts.
One popular 'Blaise and Harry boyfriends fanfic' is 'The Unlikely Bond'. It has a great plot where Blaise and Harry start off as rivals but gradually develop a deep emotional connection. The author does an amazing job of portraying their relationship growth, from hesitant friendship to a loving relationship.
Well, I'm sure there is. Fanfics often take elements from the original series and twist them in unique ways. A 'Harry Ginny Love Potion' fanfic could be really engaging. It might show how the two characters deal with the implications of a love potion. Maybe Ginny suspects that Harry's feelings are due to a love potion and she has to decide whether to trust him or not. Or it could be that a love potion was used on Harry in the past and it has some lingering effects on his relationship with Ginny, which would make for a very complex and exciting story.