=Underpants AU= Sans x Reader

I know what you're thinking. Why would I make this? Idek tbh! Dis is not lemon btw! Anyway, plz enjoy my trash sm0l children!

~Y/n was always a goofball on the surface world. Infact sometimes annoying! One day her silliness went too far and suddenly it was dark. She felt as if she was in a whole world that was made for her from there and on!~