The younger characters like Lucas and Max might get really excited about the fanfiction. They could see it as an extension of their own adventures. They might start imagining themselves in the scenarios written by the fans. It could also inspire them to think about their own actions in different ways, like if a fanfiction shows them facing a new type of danger in the Upside Down, it could make them feel more brave and ready for future challenges in their real story.
Stray Kids, on the other hand, would also be very concerned. Bang Chan, as the leader, would take charge. He might start asking questions to figure out what exactly happened. Felix could be bringing water or something to make Y/N feel better. Lee Know would be standing guard, making sure no further harm comes to Y/N while they are in a vulnerable state.
A great 'Stranger Things' react fanfiction idea is the characters reacting to different fashion trends over the years. Eleven might be really intrigued by the punk fashion of the 80s with all the spikes and leather. The gang could also have a good laugh at some of the more out - there fashion trends from the 90s and 2000s.
Y/N should have their own goals and dreams. If they're interested in becoming an Auror, that can shape their actions and decisions. Their reactions to Draco should be based on their personality. If they're a shy person, they might be more hesitant around him. And make sure their dialogue is natural. Don't make them say things that are out of character just to move the plot along. For instance, if Y/N is a studious type, they're more likely to talk about books or spells when interacting with Draco.
First, really know the characters well. You need to understand their personalities, their likes and dislikes. For example, Dustin loves science, so if you're writing a reaction to a scientific discovery, his reaction should be more enthusiastic. Second, create a unique scenario for them to react to. It could be something as simple as a new type of food or as complex as a new dimension. Third, keep the dialogue in - character. They should talk like they do in the show.
They might immediately stop the concert. The members would be really worried. For example, Jin could rush over to where Y N is with a concerned look on his face. He might ask the medical staff what's wrong and offer words of comfort.
Some would be shocked. Take Nancy, for instance. If she saw fanfiction that delved into her romantic relationships in new and unexpected ways, she might be taken aback. She's used to her story being told a certain way in the show, and this new take would be quite different.