[Undertale] Sans X Reader - Repeat, Eternally

Chapter 9 ~ Sans, of Homely Welcoming

He coldly stared at you, and you felt the hair on your neck raise.

"What name did you just say?" He repeated.

"W.D. Gaster." You whispered. He trudged closer.

"I didn't hear you. Mind repeating that..." His eye lit up, a brilliant blue. "...Kiddo?"

"W.D. Gaster." You said, a little louder than before. A bone slammed into your stomach, knocking the air out of you entirely.

Your back smashed into a tree, and you slid down the trunk, coughing. "Sans, wa-"

"And to think you almost had my trust, Kid." You felt yourself rise into the air, and were flung into another tree. You began to cough up blood. Your internal organs must be in severe need of healing.

"Sans, I-"

He raised his hand once more, and you could tell this magic was taking a toll on him as well. Before you could say anything, however, your body was slammed against another tree, and the pain was clouding your mind. You were aware of your own pained scream.

"You're makin' it easy for me this time, kiddo. I really appreciate it!" He slammed you in between two trees as if you were a ball that was bouncing back and forth between two children, but at a faster pace. He finally stopped, and you were dropped to the ground rather roughly.

You heard the crunch of snow as he stepped closer to you. As you gazed upwards, you saw nothing but pure fury and hatred.

"I don't know who you think I am, but I've never killed your brother in my life!"

Sans eyes went black.

"It's not nice to lie, buddy."

"I'm not lying!"

The ring of your cell-phone interrupted our little talk. He chuckled.

"Better answer that, kid. I'll give you one last call before I kill you."

You fumbled for your cell-phone, flipping it open.

"T-Toriel?" You stuttered. Sans seemed mildly suprised by your reaction.

"Child...I..." Toriel sounded weak. "I couldn't stop the... human... I'm using my final moments to tell you...stop them, at any cost! Stop...Fri.."

You heard a poof. Sans stared at the phone intensely.

"That was..." He whispered. He seemed to recognize the voice.

"Heeeeeello? Whoever took my phone in this time line is gonna regret it. Well, hey, I have one right now... but I really prefer mine. I'm coming for you." The line went dead.

Both you and Sans were dumbfounded, in silence.

"If that was... the kiddo... then who are you?" He seemed solemn, almost heartbroken.

"I'm one of Gaster's experiments."