Undertale One-Shots

Cheater!Sans x Reader

A/N: May or may not turn into a yandere story. *le shrug* take this crap, ya fangirls and fanbois!

You walked down the driveway. 

Today was your anniversary. You and Sans had been dating for a year now. Excitement rushed through you as you clutched your present for him in your hand, heading toward your car. You had a few things you needed to do, drop by your dorm at the college, meet up with your friend, Mettaton, for a few things. You set the present for Sans on the passenger seat, and drove to your college.

You got there soon enough and entered your dorm, picking up a few papers that you needed for a project. 

You left, and went to Mettaton's. You entered his house, which he shared with Alphys. Waving slightly to Alphys on your way to his studio room, you approached the door. You knocked. "Ton-Ton! I brought your stuff!" You shouted. "One moment, darling~" his voice came from inside the room. A few seconds later, he opened the door, and took the items you offered, and quickly hugged you with one arm. "Hun, shouldn't you be with Sans now?" He questioned curiously. "Yeah, was just about to meet up with him after this." You smiled.

"Alright, darling~" 

And with that, you left the house. You checked your phone quickly. 

You: "Omw."

Sans: "Oh! Hey, uh sorry, but I'm going to have to cancel. Something came up."

You froze in place, staring at your phone. You sighed and guessed it was Papyrus or something keeping him at home. You decided to just work on your paper, anyways. It was due in a week, and you had to get it done....

...

Several days later, it was the final day for working on your paper. Sans had canceled several more times, and you hadn't seen him in the span of all those days. You blinked away the warm tears welling in your eyes, and told yourself not to worry. You decided to go to Mettaton's and work on their joint creative project. 

Entering Ton-Ton's house for about the fifth time this week, you sighed quietly. He was in the living room, sketching something on a notepad. You sat down in a separate chair. "Hey, Ton-Ton, I finished the drawing." Your project was to create a poster for your own made-up company. You handed him the poster, and gave a thumbs up. "It's great, Y/n." He said. "Great."

You spent the rest of the day there, and had gone home.

The next day, you decided to visit Sans. You grabbed some food from Grillby's, and drove to his house, bringing the present along.  You reached the door, and had the sudden feeling of dread. 

You Knocked.

Nothing. 

Pressed your ear to the wood.

An unidentifiable noise.

You opened the door, and found miscellaneous clothing items strewn over the ground. You nudged a bra on the ground with your foot. "..." you wer silent for a moment. Then you burst into Sans' bedroom, revealing two figures on the bed. They seemed to be asleep. Sans cracked open an eye at the sudden noise, and you were just standing there, dumbfounded, Sans' present in your hand. And then your vision turned blurry, and you dropped the item in your hand. "You fucking asshole." You whispered and spun around. There was swearing heard, and a thump as Sans fell while trying to scramble out of bed. But you were already gone.

You walked to your car, got in, and locked yourself inside. Sans rushed to the car door, and tried to open it, his mouth moving as he said something you could not hear. You turned the keys and started to drive away. Once you were down some random abandoned road, you started sobbing. Your phone rang. He was trying to call you. You had a few text messages.  

"How could I have been so stupid." You muttered and rested your forehead on the rim of the steering wheel.

A/n: May post a second part. Who knows?