i'm insane for you (Yandere Underfell sans x reader)

I'm actually keeping it to gender neutral terms this time go me!
the cliche description
He loved them, of course he did you read the title? They didn't even noticed he existed, and he will stop at nothing to make them theirs, even if it meant killing everyb o d y to get you to notice him.
The better description
You have been drawing for several years, not to the point where you could live a healthy life style, but you're trying, and not to mention you work a library too! Yay for being productive, but you start to notice a red skeleton coming into your place, and staring at you way more than an average human being would, however A: you don't know anything about social interaction. B: This is a monster, so this is probably normal to them, then the disappearances start happening. That's where things get interesting.
(warning because I don't trust wattpad: This will have mentions of blood, nothing to serious, because the writer is a big coward, tons of swearing, and unhealthy relationships, oh and yandere sans yay!)
(expect a cover this after noon or tomorrow)