~Why do you care~ [Underfell Sans X Reader] [•COMPLETED•]

~The lab~

HAPPY LATE CHRISTMAS!!

It was also my birthday a couple of days ago as well so yey!~

In this chapter, it's Christmas. Yes, I'm late shuddup.

I'll try to make it good.

~Reader's P.O.V~

"Gaster Sans? As in-"

"As in assistant of Gaster. He has very important matters to discuss with all of you."

You hesitantly looked over at Error, who had many different emotions on his face. The one that stuck out the most was anger.

"Why would I go anywhere near that lonely failure after what he's done."

He straightens up, his height towering over yours.

"Your anger is understandable.. But you must understand that I've been tasked to bring you beings to Gaster.. In any way possible."

Fell stepped close to G Sans, balling his fists.

"I don't like threats, buddy."

The taller skeleton surprisingly didn't lose his temper. He just calmly looked down at Fell.

"Yes.. Well, I'm not the biggest fan of skeletons with ego's higher than they are so.. I'm guessing you've chosen the hard way?"

Ink opened up his palms along with Error, both of their powerful eyes gleaming in defence.

"Bring it.."

He chuckled, rolling up the sleeves on his jacket and flaring up his right eye (is that the powerful one? Idk.)

"Good night, boneheads."

"Wha-"

It happened so quickly.. He threw some kind of powdery silver dust at you all, making everyone but you pass out.

Although you dodged most of it, it still affected you.

You rubbed your eyes as the sound of ringing filled your ears with all you could do is watch your friends drop one by one.. And Frisk.

It was cloudy around you from the dust, making it hard to see.

You weakly grabbed a fistful of grass and tried to pull yourself forward only to be stopped by bony hands dragging you back.

He held more dust in his hands and rubbed it over your eyes gently, using his other hand to run a finger down your jawline.

"Forgive me for this, hotness."

Then everything went silent..

Everything went black.

-Later-

You woke up groggily, wiping your eyes.

You attempted to stretch but your foot touched something that zapped it, making you jolt up in surprise, retreating your foot back.

When your eyes fully adjusted to the light, you saw that you were in a big white lab of some sort.

In a cage..

The cage was attached to a chain that was attached to the roof so you were basically sitting up there with your friends cages next to you.

"Ugh.. Where?.."

"Ah. You are awake, good."

A skeleton, a bit taller than G Sans in a white lab coat pulled on a lever, lowering your cage to the floor.

"It's much more difficult to do this if you are asleep. Ah where are my manners. I am W.D Gaster.. The only reason you can understand me right now is because I injected all of you with a serum in your sleep."

You finally understood why you were feeling so groggy. He sedated all of you.

"I can sense your spirit. Is it how they say... The spirit of christening?"

G Sans from behind him cleared his throat.

"Spirit of Christmas, professor"

He corrected politely.

"Ah yes. I shall give you all Christmas hats after I do the memory reading... Anything covering that wonderful head of yours may disrupt the machine.

"M-Machine?"

You tried to grab onto the bars, only to be zapped again.

"To make sure you wouldn't escape, we laced the metal with high volumed electric shocks."

He turned around to G Sans, making him straighten up.

"Sans, go bring in the mind machine from the back"

His eyes clouded over with worry.

"But sir, the machine could still be unstable! We don't know the negative effects of-"

His sentence was cut short by Gaster wrapping his fist around the front of his shirt, yanking him forward.

What Gaster said next brought shivers down your spine, his voice turned dark and serious

"Do not talk back to me boy.. Don't you remember what happened to your brother when he didn't follow instructions?"

Gaster released him, letting him stand there as memories seemed to flood back to him.

"Right.. I apologise. I'll bring it in right away."

His voice sounded dull... Lifeless.

I wonder what happened to his brother