This is not your regular Undertale AU. This is the world of UNDERTALE NEON. Instead of using a Human change or a swap AU, I have decided to do something different. I don't know about you, but when I think of the neon color palate, I think of something like a retro arcade. (like the picture below)

So I'm using a game like undertale, which you could consider retro because of its 8-bit art style, and putting a colorful twist to it. And because I think of an arcade when I think of neon, I feel like the environment should be more electronically advanced because the game will take place ten years in the future.