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.
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.
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.
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.
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.
There are also some original characters created in fanfiction who are potion geniuses. These characters can bring new storylines and perspectives to the world of Harry Potter potions. They might have unique ways of brewing potions or discover new potion recipes that change the magical world.
There probably is. Fanfiction allows for all kinds of creative interpretations of existing stories. Given the popularity of the Harry Potter series, many fans like to come up with different relationship combinations. However, the quality and nature of these fanfictions can vary widely. Some might be more focused on the relationship aspect, while others could incorporate a lot of the magical world elements along with this particular pairing.
One great fanfiction could be about Tonks using her Metamorphmagus abilities to go undercover in the Death Eater ranks. She could change her appearance to look like one of them and gather crucial information for the Order of the Phoenix. This would add an exciting element of espionage to the story.
I really like 'Tonks: The Hidden Powers'. In this fanfiction, it shows Tonks discovering some new and unexpected magical abilities. It's quite creative. 'Tonks and the Forbidden Forest' is also good. It takes Tonks on an adventure in the Forbidden Forest where she has to face many dangerous creatures. And don't forget about 'Tonks' Love Story' which gives a new perspective on her romantic relationships within the wizarding world.