Well, if Undertale could watch Undertale fanfiction, it could lead to some chaos. For example, Sans might make jokes about the wild scenarios in the fanfics. Papyrus, on the other hand, might be eager to correct any misinformation about himself. And Flowey could use it as a way to manipulate things further, seeing how the fans view the characters and using that knowledge to his advantage in this strange, meta - situation.
Some characters might be amused. For example, Sans would probably make some witty remarks about the fanfiction's plot twists. Papyrus, on the other hand, might be a bit confused at first but then get really excited if he finds a heroic role for himself in the fanfiction.
No, in the game's lore, there's no indication that Undertale has the ability to watch fanfiction. The game world is focused on its own story and mechanics, and fanfiction exists outside of that official world.
I don't know who xqc is in this context without more details. It could be someone's username, a streamer, or just a name given to a character in a particular situation.
I'm not entirely sure specifically what 'xqc reacts to neuro story' is about without more context. It could be that xqc, perhaps a person or a character, is reacting to a story that has something to do with the neuro (which could potentially refer to neuroscience, neural networks, or something related to the nervous system in a more general sense).
One popular 'Overwatch Reacts' fanfiction could be the ones where the Overwatch characters react to different timelines or alternate universes. For example, they might react to a world where the Omnic Crisis was never resolved. Another could be their reactions to new heroes joining the team. It's all about exploring the characters' personalities through these reaction scenarios.
Well, it's not really acceptable. The Undertale community is supposed to be inclusive but also appropriate. Fan fiction should focus more on the positive aspects of the game, like the story, the characters' development, and the unique world it presents. NSFW content, especially with a sexual orientation focus like 'gay' in this case, can make a lot of fans uncomfortable and may even violate community guidelines in many platforms.
In a comical fanfiction, most of the characters would enjoy it to some extent. Sans and Papyrus would be great additions to a comical story, and they would probably laugh along with the funny parts. Frisk, depending on how they are portrayed in the fanfiction, would either be the source of the comedy or be reacting to the absurd situations. In a more serious and political - themed fanfiction about the Underground's society, Asgore and Toriel would have deep thoughts. They might discuss among themselves how the fanfiction's view of their leadership and the society they built compares to their own intentions.
It adds variety. The undertale fandom is huge and diverse, and frans lemon fanfiction offers a different take on the characters and their relationships. It gives fans who are interested in this particular pairing more content to enjoy.