.

Not with a Bang but with

Notes: So, this chapter ended up being split in two – what would have been the rest of Chapter 3 will now be Chapter 4. Seeing as the first half alone ended up being 7.4k words, that was probably a good call on my part.

And to everyone who bookmarked, left kudos, or, especially, left a comment/review: THANK YOU! And don't forget to check out the NWABBW blog under the tumblr "nwabbw" for special extra content!

Trigger warnings for child abuse/experimentation, and Gaster being his usual dickish self.


CHAPTER THREE:
Darker Yet Darker

oOo

When Sans was ten, he dropped out of school.

oOo

"Let us begin."

Head bowed, Sans screwed his eyes shut, concentrating. He just had to make it to the other side of the room. He could do that, no bones about it.

The other side of the room. Twenty feet.

Sans had gotten used to his magic a long time ago, had gotten used to using his magic attacks. His other abilities, however…

Skeleton monsters were unusual enough as it was – their ability to speak and communicate in their own unique fonts, each one particular to its owner; their penchant for expressing emotion by way of eyeglowing; their natural predisposition toward blue magic – the list went on. Some skeletons even had certain magical tendencies of incredible, exceptional power, completely separate in nature from the ordinary magic attacks innate to all monsters. Abilities like teleportation, levitation, and telekinesis.

No skeleton had been able to teleport or use telekinesis since before the war – Gaster could do neither, though he had his magic hands. Of course, most of the skeleton species had been wiped out in the war, and those that had survived had long since died out. All but Gaster. And in the limited historical records of skeleton monsters, none had ever been able to do both.

Determination, however, had a way of kindling a soul's magical energy signature, of empowering its host beyond reasonable possibility.

Sans was special.

And he could – he would – get his magic to co-operate with him, and teleport twenty feet to the other side of the room.

Teleportation - the ability to cheat the laws of physical space. Think of it as... taking a shortcut across a material plane. Arriving at a destination faster than you would have if you'd walked.

Sans summoned every ounce of concentration he had, calling on the magical energy that burned at his very core, screwing his eyes tighter and balling his hands into tight fists, willing himself to glitch

The surface that was now beneath his feet was not cool tile – wherever he was, he wasn't on the ground. Sans opened his eyes. He'd only teleported about two feet across the room, and landed on top of a table, in dangerous proximity to Gaster's mug of coffee. An inch or two to the right and he'd have spilled the coffee all over the calculus test that waited for him for when the day's training was through.

He quickly scrabbled back down onto the floor, preparing himself for Gaster's response.

"Try again. Ten feet this time. Aim for the computer desk."

Closing his eyes again, Sans sucked in a deep breath, concentrating as hard as he could. Harder. This time, he shortcut immediately. For a moment he thought he'd really done it, he thought he'd passed the test, but as he opened his eyes it became clear he'd undershot again, having landed mere inches to the right of his original location.

The sound of Gaster's pen, scribbling notes from where he stood in the doorway. His gaze flicked down toward Sans a moment. "All right. One more try, same place as before. Again."

Sans panicked, glitching immediately. This time he overshot completely, landing just behind Gaster and out in the corridor.

He felt Gaster's gaze on him, cold and filled with disappointment. The sound of Gaster's pen scratching across the clipboard drowned out the distant hum of machinery, the executioner sharpening his axe. He delivered his final sentence:

"As I anticipated. A regular failure."

Sans looked down at his toes, angry and ashamed.

"It isn't my fault," he muttered, though he dared not meet Gaster's eyes. "This is real hard. And hey, guess what – at the end of the day, I'm still better at this stuff than you."

Gaster didn't even bat an eye. "Hmm, yes. A weak jibe – I lack the altogether ability to teleport. It is an uncommon ability found in only a few skeletons. I am not one of them, through no fault of my own, or indeed anyone's - it all comes down to chance of the draw, in true monsters. You, however, have the potential to be an incredibly powerful vessel – your energy signature is astounding for a monster of your age, most likely brought about by the Determination trials, and yet your control of your abilities continues to be remarkably poor." Beat. "Anyhow, that is certainly enough for the day, I believe."

Sans didn't give Gaster the pleasure of hearing him apologise. Instead he ignored him, slipping past his creator and making for the table he'd landed on just before. He pulled himself up to sit on it, taking the glass of orange juice that had been put out for him, draining it in two large gulps.

Gaster cleared his throat. "Sit in the chair, if you please, Sans."

Sans ignored him.

"Now."

Sans paused. He slid off the table and sat down in the chair, pulling the calculus test over to him. It was eleven pages thick, and a glance at the first page told him that it wasn't going to be much of a task: he'd be finished in two, three hours, tops. "So now I do the test, yeah? And then I can go home?"

"Yes."

Sans picked up his pencil – he realised with something of a jolt that Gaster had put out his lucky one, not that he needed it, this stuff was easy – and began.

SECTION ONE – WORD PROBLEMS

To test subject's ability to associate words with mathematical symbols

Question #1: Calculate the antiderivative of : secant of x, cubed, times the tangent of x.

Sans got to work at integrating, quickly settling for using the u-substitution.

"Perhaps we will continue with your training this weekend. Goodness knows you need it." Gaster came by the table to pick up his coffee.

Sans looked up. "Uh-huh." At least magical training didn't hurt. That wasn't to say he liked it – he much preferred math and science tests, but anything was better than the Determination trials or the sting of the scalpel hacking into his bones. He tapped the end of his pencil on the table in thought. "Could we do telekinesis?" He was better at telekinesis than teleportation.

"I suppose it makes little difference – but we can if you wish."

Sans grinned to himself, looking back down at his calculus. He finished the first problem and moved on to Question #2: Calculate the antiderivative of: the square root of x times the cosine of x. Then Gaster's voice brought him back to attention.

"Of course, it is not truly telekinesis, you do realise," he said, with a world-weary sigh. "You degrade yourself, truly. Scientifically and magically speaking, telekinesis does not exist outside of those comic books you cherish."

"Yeah, yeah," Sans muttered, annoyed. He abandoned his calculus test a moment. "But it sounds cooler if you call it that."

"Hardly. As I said, you you degrade yourself. What you call 'telekinesis' is the ability to use blue magic, with a degree of precision, upon an object without a soul."

"Well, I think telekinesis still sounds cooler."

Sigh. "If you wish to continue insulting yourself and the abilities of your ancestors, suit yourself."

"Whatever." Sans returned to his calculus test.

Gaster meanwhile crossed the room over to the computer desk, dropping his clipboard onto it and scanning over the notes he'd taken. Sans, unable to resist, began to watch as Gaster brought up one of the files he had pinned to his desktop – Sans' file. He opened several documents, and Sans tried to read what was on the monitor as Gaster muttered to himself, too low for Sans to hear.

"Seeing as it's about me, can you say?" Sans blurted.

Gaster turned in his swivel chair to look at him, and Sans braced himself, expecting the magic hands to appear and deliver him a good, hearty swat over the head. Instead Gaster answered him, his tone indiscernible, "There appear to be – " he paused delicately – "complications… involving you and the Determination trials."

"Complications like how much it hurts?" he muttered. Well. Now Gaster was definitely going to hit him, so he was surprised when he was instead graced yet again with a response.

"The pain is an unfortunate and immediate result of the administration of the Determination solution: it will continue to react poorly with your system even as you develop a tolerance for it and as we continue to slowly increase the dosage you receive. No, this is… different. An unfortunate… reaction, shall we say, I did not anticipate."

"What reaction?" Sans paused. "Am I gonna die?" He'd almost died once, when he was eight, from a Determination overdose. His resulting illness had resulted in a host of problems with his HP, and he'd been too weak to get out of bed for over a month.

"No, no, nothing to that extreme; you needn't be so melodramatic… " He trailed off.

"Then what?"

Gaster got up from his chair and held out a hand. "If you want to know, come."

Sans shrank back a little, eyeing him warily. "Wha – why?"

"Just come." He gave an impatient huff. "I am not going to inject you with more Determination, or anything else, if that's what you're afraid of. Come, now. I am simply going to make some basic measurements and take a small bone sample for further affirmation. Be sure I'm right."

Sans sighed, but pushed the chair back and got up, stuffing his lucky pencil into his pocket just in case. Gaster took him by the elbow and half-led, half-dragged him over to a corner. He fumbled around in a drawer, at last selecting a tape measure and a small, handheld scanner that Sans knew performed quick, rudimentary scans. He much preferred it to the main scanner or the MRI machine, the last of which still scared him a little.

He stood stock-still as Gaster ran the scanner up and down his body, and as he took measurements of his height and arm length using the tape measure, standing straighter and taller when Gaster bid him. At some point the scientist also lifted his shirt and bit into his spine with… something, something sharp that made Sans flinch, though he couldn't see what Gaster was doing, and when he twisted around to try and look, he was swatted pointedly over the head.

At last, it was over, and Gaster returned to the computer, leaving Sans to rub at the now-stinging spots on his spine. Gaster started muttering to himself again, comparing the notes he'd just taken with the readings on the computer and the scanner. Sans must have waited for ten minutes before Gaster finally spoke up.

"It has been quite a while since last I measured your height – a few months. In that given period of time, most boys of your age would be expected to grow at least somewhat. And yet it appears that… Ahem. The Determination seems to have interfered with your physical development."

Sans' brow wrinkled in confusion. "Huh?"

"Your growth, namely."

"My growth? Like how tall I am?" Sans had always been one of the smallest kids in his class, except for some of the rodent-like monsters.

"Yes. Let's see, how to put this simply… The Determination appears to have stunted your growth. You remain at the same height you were the last time I measured you, and the time before that. By all likelihood, you will remain permanently at the height you are now; and if you do grow, then it will not be very much." Gaster seemed to be thinking for a moment. "I apologise."

Sans found himself looking down at his toes again, Gaster's words reverberating in his skull. Gaster may have put it "simply," but the gist of it was that he wasn't going to get any taller. He was going to stay like this, at the height of a considerably small ten-year-old, forever.

And it was Gaster's fault.

Because of the Determination trials. The trials Sans had been mentally willing to come to a stop since they'd first begun two and a half years ago, back when he was seven. Wasn't he filled with enough of that Determination stuff already? Gaster had said Determination was key to shattering the Barrier, but Sans sure didn't feel like he could do anything about it.

He clawed at his inner wrist, rocking back and forth on his heels.

"Can I go back to my calculus now?" he asked at last. "Stoppin' me in the middle of it to randomly check me over's kinda distracting. You're making me lose my train of thought."

Gaster waved a hand, and Sans returned to the table. His gaze lingered on Gaster a moment, who began riffling through a stack of papers and had resumed muttering to himself. Then Sans sighed, and pulled his pencil from his pocket, turning his attention back to the test.

Question #2: Calculate the antiderivative of: the square root of x times the cosine of x...

oOo

The next few months passed by uneventfully, and the "complications" associated with the Determination trials were not brought up again. Sans figured this made sense. It was like his broken eye – there was nothing he, Gaster, or anyone could do to change anything, nothing that could be done to fix him. And, if he was being quite honest with himself, if he was going to be stuck at a kid's height for the rest of his life, he didn't want to be reminded of it anymore than he had to be. His classmates would soon noticeably outgrow him – and one day so would Papyrus, he figured – but that didn't mean he wanted to linger on it.

In those months, Sans saw very little of Gaster – even the biweekly Determination trials drew to a near-halt. On one of the few occasions Sans saw Gaster, when he was called down to the labs, he asked him what he was up to. Gaster's reply was vague – not that Sans had expected anything more. Something about his studies of the Barrier, he said – something was afoot in the CORE, and he was making "great progress," whatever that meant.

One innocuous Saturday, Gaster came to look for him in his bedroom for the first time in more than a year.

He shared his bedroom with Papyrus. Papyrus was cross with Sans for having finally thrown out the enormous pile of pencil shavings that had accumulated on his side of the desk – apparently he'd been COLLECTING them, Saaans! He was now sprawled on his front on the floor, working hard on a fifty-piece jigsaw puzzle, which he'd insisted on doing all by himSELF. It was unclear if this was because Papyrus was still upset with him, or because he really did want the satisfaction of having completed the jigsaw on his own. Sans suspected the latter. He had a head for puzzles, his brother.

Sans was curled up on his bed, absorbed in a book on astronomy – one of his favourites – that Gaster had given him years ago, as an apology for breaking his eye.

It was quiet for a change; Papyrus was completely focused on his puzzle. On most days he amused himself by running about the house, shrieking at the top of his voice, climbing on the furniture, bouncing on his bed, and generally causing a huge ruckus.

The knock on the door startled them both. Gaster didn't wait for an answer before opening it. Sans realised he hadn't seen him for nigh two days, and the scientist looked terrible. His lab coat was stained, and he looked as if he hadn't slept in about a week. As far as Sans knew, he hadn't.

Good. He hoped he was tired and groggy. He hoped his head hurt because of it.

Gaster said nothing at first, scrutinising each of them with a strange new light in his eyes, making Papyrus abandon his puzzle and join Sans on the bed. Sans wondered if he'd had one too many coffees.

"You will come with me," said Gaster, and Sans drew Papyrus closer, meeting his creator's gaze warily. His voice sounded strange – cold as ever, but there was something else behind it now, something Sans hadn't heard in years, not since the first day of the Determination trials. And there was something else as well, something Sans couldn't quite place but that sent a shudder down his spine.

"C'mon, not today… it's Saturday," he muttered.

"Both of you. With me."

Sans stiffened and swallowed, but he stood, picking his brother up. Papyrus just buried his nasal bone in the fabric of Sans' blue-and-green striped sweater and nestled himself closer, the pencil shavings apparently forgotten. In Sans' experience, his brother had only shied away from Gaster a handful of times. And he'd never, ever seemed quite this afraid, this unnerved. Papyrus spent most of his time around Gaster bouncing around him and trying to give him a hug. That it was so very hard to give him a hug made it a fun and challenging game.

Not that that was surprising. Everything about Gaster – his mannerism, his tone, his voice, even the way he stood – exuded a profound wrongness. What frightened Sans the most – for yes, he, too, was afraid, somehow more afraid than he could remember feeling in years – was that he couldn't quite place a finger on what was so very unsettling, just what frightened him so. Gaster was always cold, and brusque in his tone. Efficient. He always looked at him and his brother this way. But now something unnameable had been added to the mix. Something had shifted, making Sans feel much younger than his ten years.

"Where to?" he asked at last. He cocked a brow in the way he might have if Gaster had told him he was going to start a new series of experiments. "The labs? What, you wanna poke at both of us now? Do we get to do it in the same room?"

Gaster held his gaze for a second. Then, without answering, he turned on his heel and left the room. Sans glanced at his brother, then followed.

Sans had been expecting Gaster to turn his soul blue, but he never did. Perhaps he might have done if he or his brother had resisted. As it happened, neither of them did. Papyrus clinging to him like a baby koala monster, Sans allowed Gaster to lead them through the network of New Home's streets – two blocks north, then a right and a sharp left. Across the square, where a few kindergarteners were playing a game with a ball. They stopped to stare at Sans and Papyrus as they went by, struggling as ever to keep up with Gaster's long strides. The scientist seemed to be walking faster than usual. Around a corner, then straight for three blocks before reaching the entrance to labs.

In the elevator, Papyrus asked what was going on, and please could they go back home now; he was sleepy. Gaster glanced down at him, still with his arms around Sans' neck and his face peeking out from his sweater, then gave a vague hum by way of an answer.

Sans didn't dare to press the matter.

The elevator dinged, doors sliding open like a set of jaws into the great, dark belly of the lower labs.

It went without saying that Sans knew the labs more than well. He could have navigated their corridors blindfolded. And perhaps it had something to do with Gaster's ominous behaviour, or perhaps he was just being paranoid, but stepping out onto the tiled floor behind his creator, the labs suddenly seemed a vast, dark place, foreign and frightening.

Four sounds filled the air: the distant hum of machinery; Sans' shaky breathing; the click of Gaster's shoes against the tiled floor, the sound arriving with metronomic precision and echoing off the walls. The telltale pattering of Sans' own bare and bony feet against the ceramic rounded everything off very nicely.

Following Gaster, Sans had been expecting him to lead them into the examination room, or else the room where he did most of his magic training and completed many of his intelligence tests – not that Gaster hadn't surprised him in the past. Instead, he turned a sharp left into a corridor Sans wasn't sure he'd been allowed to go down before, and it was less than a minute before he identified it as the one containing Gaster's offices.

"You… do realise we're still with you, right?" he asked as he followed Gaster into a room towards the end of the corridor. Predictably, Gaster gave no response.

The room was small and cramped, barely larger than the bathroom in their house, and there was nowhere to sit. In one corner sat a large machine on wheels, about twice Sans' size, all shiny metal and vaguely box-shaped. There seemed to be a small monitor on one side of the machine, which was switched off. All manner of strange wires emitted from it, plugged into an outlet in the wall. Every couple of minutes the machine emitted a series of irregular little beeps.

On the other side of the room, against the far wall, was a much larger monitor screen, stretching nearly from floor to ceiling, in front of which sat a control panel roughly at the level of Sans' shoulders. A series of random characters scrolled steadily down the screen. This was what seemed to have captured Gaster's interest, and he stood with his back to Sans, inches in front of the screen, hands resting against some switches on the control panel.

"What is that?" Papyrus murmured, but Sans just shook his head. Glancing hurriedly at the machine and readjusting Papyrus' weight, he took a step closer.

"Gaster," he tried again. "Why'd you drag us down here? What's going on? What do those characters mean? And what's that machine thing?"

Gaster glanced over his shoulder, then blinked as if he'd only just noticed the brothers were there. He stepped away from the control panel, clasping his hands together and looking down at them.

He smiled.

"Ah. Sans. Papyrus."

"What's your deal?" he asked, warily cocking a brow and staring up at him.

Gaster's smile widened. "Do you recall I have been pursuing – how shall I put this – independent studies?"

"You mean studying without hurting us?" Sans muttered, glowering up at him.

"Unless you can aid me in my analyses of the Void, Sans, then I doubt you or your brother would be of much use."

"The Void?"

"Yes. I've mentioned it in passing, though I don't suppose you were listening." Gaster glanced over at the screen, tilting his head contemplatively. "What you see before you are readings I have been collecting from the Void."

"Yeah," said Sans, cocking his own head to one side. The characters continued scrolling down the screen like an army of spiders out on business. Studying them further, Sans realised they consisted mostly of zeroes and ones. Papyrus wriggled against him in an effort to get free, and Sans paused before setting him down on the floor, turning his gaze back to Gaster. "You didn't even answer my question. What's the Void?"

"You really weren't paying attention, were you?" Gaster hummed. "Simply put, the Void is the space – or lack thereof – outside spacetime. It is the emptiness on the edges of the universe."

Sans thought it sounded a little like something from his comic books. "But if it's outside the universe, how can you get information from it? You ain't making any sense."

Gaster did not correct him with an aren't as he normally would. Instead, he turned his attention to the computer monitor once more. "Here in the Underground, we are isolated from the rest of the world by means of the Barrier."

"No kidding," Sans muttered.

Still Gaster didn't comment on his gibes. "We are not just isolated from the rest of the world in that we cannot access it. We are cut off from it completely, existing in a near-separate universe in our own right – a bubble universe, you might call it. It is a fitting description. A closed system. The Barrier cordons us off from the rest of the universe, so we follow our own unique timeline, in the limited world to which we are confined. We experience that timeline in a linear fashion. Now suppose one were to… manipulate the timeline as they pleased. Any damage or alterations made would be contained within the Underground, thanks to our lovely Barrier. However - to rewrite and rearrange time would cause great damage to the fabric of spacetime: the material of our little universe is terribly fragile. And so – " Gaster gestured to the screen – "we are left with tears."

Sans was trembling hard enough that he could hear his own bones rattling. He barely understood the half of what Gaster was saying, and even then, he didn't see what it had to do with him or his brother, with the Determination trials or his purpose in destroying the Barrier. Quite frankly he was too scared to care very much. He wanted to run back to his room and read from his comic books, or do math, or play with Papyrus, do whatever it took to just forget everything. He'd never wanted to more in his life. "Why've you dragged us down here? What's this got to do with anything?"

"Of course, only an anomaly – you know what an anomaly is, don't you, Sans? – could ever actually manipulate the Underground's unique timeline. Bend it to their will. To an anomaly, our universe is a simple plaything. A game."

"Yeah, so?"

By way of response, Gaster held up a small black box-shaped item, produced from the pocket of his lab coat, to his mouth – a Dictaphone, Sans realised.

He followed Gaster's gaze to the monitor screen again. The characters continued scrolling down it, the machine in the background continuing to emit erratic little beeps, and the longer Sans stared at the monitor, the harder it was to look away. He stared at the scrolling characters until they were all he saw, zeroes and ones and, very occasionally, other characters, filling his left eye socket, their movement constant, zeroes and ones and zeroes and ones and zeroes and ones, never-ending scrolling. As he stared, hypnotized, something dark gripped at Sans' soul, as if those characters were reaching out and touching it, their fingers long and cold and sticky. He could feel them, feel them as they scrolled down the screen.

There was a click as Gaster began recording, snapping Sans to attention once more. "Void observation logs," he said, and if his voice had had a strange, unsettling tone to it before, now it chilled him to the marrow. In that moment Sans realised just what was wrong with Gaster's voice – for the first time in his life, he was having trouble understanding him. "Entry Number Seventeen."

"Dark," he said, and his voice lowered and trembled slightly. "Darker, yet darker.

"The darkness keeps growing...

"The shadows cutting deeper… "

From behind, the clicking of bare feet on tiled floor. Papyrus had gotten up from where Sans had set him down, and pattered over to his older brother. He slid his hand into Sans' and buried his face in his side. Sans picked him up again.

"Photon readings ṋ̰̖̪ͅe̤͖̻g̶̻̣͉̤̟͉̟a҉͔̲t̹͕͔͍̞͉͉i̙ve̦̼̕…"

Gaster pressed his free palm against the monitor. The characters continued running up the screen, some of them visible through the hole in his hand. They made the hand look more complete, somehow, as if they had become a part of him. He leaned closer and Sans could just see him tighten his grip on the Dictaphone.

"This next e̹̬̗͠x̧͏͉̘̺̖͘p͏҉͍͕̕ͅe̘̱͓̝͙̣̩̺r̴̼͍i͓̖̹͜͢m̥̙͖̯̗͟ḙ̺͝ņ͈̠̟͉̞̩̙t̵̤̮̭̮͔͕̣… s͎̻͔͍̟̹̭͜ȩ̖͖e̤̜̭̝̩͖̖ͅm͏̰̬̭̹͓̼̹ͅs̨̟̬̜̣͎̺̖̱.̷̯̻̗̪̳͔̼̹̼.̬̝̯͕̻͉͔͙͡.̬̥̦̩̼̠̕ ̬̭̫̰̱v̮̺̜͍̪ͅe̹̤͓̮̥r̠̳y̨̛̤̩̳͇̭̬͔͟ͅ.͕̩̱̠̕ͅ.͏̶̡̙͍͓̱̯͔̱̱͈.̧̹̣̗̭͖͈̯ ̴̼̳͇̱̼͉̩̦v̜͕̳̭̘̞̬͈͘͟e̷̠̻̗̱ͅͅr̦̱͍̮͘̕y̢̨̹̹̹͉̰̰̻.͇̜.̯͙͇͖̭͔.̛̜̠̺.̷̖̣͚͍̻ ̯͠i̳͟͠n͇̘̱t̶̨͔̞̙͙̰e̛͖r͈̮̮͔ͅe͖̪͍͎͈̫̠͈s͈t͕̟̻i̢͖̯̻̺͍͖̕ͅn̦͔̘̩̟̺͚g̟̦̞̟̭̙͝.̧҉͉͈"

He paused then, a lengthy trail of a pause that slithered up Sans' back. Then he turned, looking at the brothers with a smile on his face that was far too wide even for a skeleton's permanent grin. "… what do you two think?"

"I think I want you to stop and leave us alone. I wanna go home," said Sans, pulling Papyrus closer.

There was no response, though the Dictaphone was switched off.

"Gaster," said Sans loudly. "I wanna go home. I wanna take Papyrus and I wanna go back home." He struggled to keep the fear from his voice.

Gaster blinked several times, as if waking from a dream. "Yes. Yes, of course. You should both be going back home." When Sans lingered, eyeing him warily, Gaster summoned a magic hand and gave him a slight nudge. "Well, go on, then. If you wish to leave, then do so. I need to work."

Sans eyed him another moment. Gaster already seemed to have forgotten they were there. The child lingered for a beat, then he turned, and made his way out the lab complex and toward the elevators, Papyrus in his arms. Neither of them said a word to each other the entire way home.

oOo

Back in their bedroom, Papyrus toddled over to their desk and plopped down. He looked to be in something of a daze as he picked up a crayon and began to draw something on the back of Sans' math homework. Sans barely noticed.

He stripped off his clothes, changing into his pyjamas, desperate to do something, something mundane, more mundane than even math, anything to take his mind off Gaster's cold, emotionless voice, off the pressing feeling he intended something, something great and very, very dark, something to take his mind off the void

Once he'd changed, Sans flopped down onto his bed. He curled onto his side and closed his eyes, drawing the book he'd been reading to his chest. In a minute, he'd read it.

"… Sans?"

Sans opened his eyes. Too soon.

He smiled a little, propping himself up on one elbow and reaching out to his baby brother. "Hey, bro. You tired?"

Papyrus nodded, then launched himself from the desk onto Sans' bed. He wrapped his arms around his brother's neck and clung to him tightly, and Sans realised with a jolt he was trembling so much his bones rattled.

"Hey. Hey," he crooned, stroking his brother's skull, gathering him closer. "Hey, it's okay, Paps. I got ya. I got ya." He clicked his teeth against the top of his head, and Papyrus cuddled closer still.

"That was SCARY."

"Yeah. Yeah, I know. Shh. It's okay. Shh."

"Why was Daddy acting like that?"

Sans stiffened. "He's not our dad, Papyrus."

Papyrus immediately sat up straighter, all three-year-old indignance. "YES HE IS!"

"No, he's not," Sans replied, tightly. "We don't have a dad, Papyrus. We just got each other, okay? We don't even need a dad."

"HE IS TOO!"

"No, he's not, I said!" Sans snapped, frustrated now. "He isn't our dad. He's just Gaster, got it? He's just Gaster. You're my brother, but he's still Gaster! He doesn't care about us, Papyrus! He doesn't love us, but I do. Okay?!"

Papyrus glared at him with all the defiance of a toddler. "HE DOES TOO LOVE US. He, he, once when you were at school, he, he PETTED MY HEAD! And then he maked me oatmeal."

His words hit Sans like a punch. "No, he didn't."

"I like oatmeal. It's my FAVOURITE."

"He didn't do that, Papyrus."

"DID TOO!"

Sans scrutinised his brother's little face, trying to find the lie there. He couldn't. And he knew that even for a three-year-old, Papyrus was a terrible liar.

"Well, then he didn't mean it, Paps. He was just saying that to make you do what he wanted." Something clutched at Sans' chest and made him turn away. He couldn't say what it was.

It wasn't envy, though.

That would be stupid.

"Did TOO mean it," Papyrus muttered, and Sans could hear him sniffling.

Sans sighed, rolling over to face him again. Tears now streamed down Papyrus' cheekbones, angry, violent tears. "Okay," he said at last, pulling him into a hug again. "I'm sorry. Okay. Okay."

Papyrus relaxed and sniffled, rubbing his sleeve across his eye sockets. "Tireddd..." He rested his head against the crook of Sans' arm, sockets drifting shut.

Sans ran his fingers absently up and down his brother's arms. Except for the odd imperfection or miniscule pinprick where a needle had gone in, the bone was smooth and unmarred. The same could hardly be said for Sans' own arms, rough with years of scritches and cuts and faint cracks that served as a reminder of old breaks and fractures. You could see, too, where the bone had been hacked at and chiselled away if you looked closely enough – "samples," Gaster called them. His hand hit a deep groove in his brothers' right humerus and he frowned.

"Paps?"

"Nyeh?" Papyrus didn't open his eyes, shifting against Sans.

Sans' frown deepened. "Bro? What happened here?"

Papyrus cracked open one eye socket, then the other. He tugged his arm pointedly away, studied it as though seeing the groove for the first time, then shrugged. He closed his eyes again, but Sans was having none of it. Something was beginning to boil in his chest, fear and desperation and anger – mostly anger. He shook Papyrus by the shoulder, and the younger skeleton opened his eyes again.

"Hmnnnghhh… "

"Papyrus. What happened?" he asked, struggling to keep the desperate hitch from his voice.

Papyrus whined loudly and tried to roll over, but Sans caught him by elbow, leaning over him.

"What's it from? Marrow extraction?" They both got marrow extractions on a bimonthly basis, and they were nothing to fuss about. Even as Sans said it, he knew it wasn't the case. The arm wasn't exactly the ideal place from which to extract bone marrow. And what kind of marrow extraction left a mark like that?

"No, sillybones!" Papyrus giggled at his brother's foolishness, because he too knew how bone marrow extractions were. "Da – he just… " Papyrus shrugged. "Don't know."

"What did he use? A sharp thing?" Sans demanded. "Like a scalpel or pick?"

Warily, Papyrus nodded.

"Did it hurt?"

A pause. Nod. Sans closed his eyes, shoulders slumping. He thought he was going to be sick.

"Did he inject anything in you with the needle?"

"No… Saaaaans?" Papyrus tugged on his arm. "Slee-eep…"

Sans forced himself to open his eyes and look at his brother's face rather than the chunk that had been taken out of his arm. Papyrus was sitting up, rubbing at his eye sockets sleepily, looking for all the world like there was absolutely nothing wrong. He probably didn't even know anything was wrong. Sans hadn't known any of that kind of stuff at his age, either.

He just looked like a cranky toddler who wanted to go to sleep. And if Sans kept him up with questions he didn't understand for much longer, he was probably going to throw a tantrum. Sans didn't feel like dealing with a tantrum.

"Right. Okay. Sorry. Let's go to sleep. Great idea." He lowered himself back down onto the bed, and Papyrus cuddled up next to him for the third time that night, closing his eyes and sticking his thumb in his mouth. Skeletons couldn't suck their thumbs, exactly, but they could gnaw on them lightly, and Sans hoped his brother would break the habit soon. "You're okay. You're okay."

"Nyeh," was all Papyrus said, sleepily.

"I hate him," Sans muttered a good five minutes later, finally closing his eyes. Hate was a strong word, and he thrilled in being able to wield it.

But Papyrus' body had already gone limp with sleep, and Sans sighed, finding himself smiling softly as he drew his baby brother closer.

When Sans finally fell asleep, he dreamed he was falling through a dark and bottomless void. The darkness seemed to be waiting for him.

oOo

"Gaster?"

The scientist was in the kitchen, brewing himself a cup of coffee, when Sans came up behind him early the next morning.

"Yes, Sans?" Gaster's tone was lazy and bored, and he didn't even bother turning around, standing in sharp contrast to the behaviour he'd exhibited just last night. Sans was quietly relieved. He wouldn't have been brave enough to face Gaster otherwise. This was normal. This Sans could deal with, no problem.

He'd all but pushed Gaster's behaviour to the back of his mind anyway, logging it as irrelevant. Because Papyrus had been hurt, hurt by Gaster, and Sans had vowed to make sure his brother never, ever hurt.

"Last night, I noticed… " He trailed off, and got to the point. "You hurt my bro. You did an experiment on him." He said it plainly, like the fact that it was.

That seemed to capture Gaster's attention. He turned around, arching a brow. "Why, yes. Yes, Sans. I did."

Something about the matter-of-fact, nonchalant way Gaster said this filled Sans with a fresh rage. He balled his small hands into fists. "You… you really did hurt him."

"I extracted a small bone sample, yes."

"That was way more'n a small bone sample! You took out a whole entire chunk of his arm! You hurt him! He's three!"

"He is three years old, exactly. I began working with you well before that age. I have respected your request to refrain from using your brother in any of my experiments wherever possible. As per that request, he has only undergone marrow extractions. And yet he is a creation, my own creation, made for no other purpose than to serve a role in my studies. Did you think I wanted another whining brat to look after for the purposes of my own enjoyment? I have put off work with Papyrus for long enough."

"You hurt him," said Sans, simply.

"I required a simple – all right, very well, admittedly somewhat large – sample of bone. Your brother proves useful to me in ways that you will never be able to fulfil."

Sans looked away. "Like what?"

"I had no intentions of making another subject. Yet after the accident with your eye, I decided that having another one to work with would be for the better – the effects of that particular experiment were drastic, unfortunate, and permanent. Would you rather have been rendered completely blind in both eyes? And as time went on, I realised that creating Papyrus came with all kinds of benefits I had not initially anticipated."

"Like what?" Sans repeated, looking back at him with new defiance. "You wanna cut to the point?"

The coffee machine dinged, and Gaster glanced at it. His coffee was ready. He poured it into a waiting mug and fetched the milk from the fridge, pouring some into his own drink, and, after considering the carton a moment, poured a glass for Sans. Only when he'd sat down at the table did he answer, hands curling around the mug. He seemed to be contemplating the gaping holes in his palms. "You'd rather I spell it out for you? Fine. Your body is, at present, filled with Determination. Every marrow extraction or raw bone sample I take is full of the substance. Cut you, and you seem to bleed. Your body is filled with Determination, and that interferes with all kinds of other tests. Having a subject who is not tainted with the solution is very useful. …where is your brother, by the way?"

"Still asleep." Sans took the glass of milk grudgingly. "So. I'm damaged."

"On the contrary. You are valuable beyond comprehension. You have insisted I remove your brother from the Determination trials, and despite the fact that using two specimens would be most helpful so as to compare contrasting results and to assess which of you is more predisposed toward the substance, I have respected your request. He is… still quite young, after all. The Determination trials would likely kill him at this age anyway."

Sans' shoulders sagged. Gaster was right, he supposed. "I know you haven't used him in those. … thank you."

Gaster nodded once in acknowledgment, sipping his coffee, and Sans gulped down half his milk.

"He is also more readily available than you are, and that won't last forever."

Sans' head snapped up. "Huh?"

The scientist set down his mug and spread out his hands. "He is not of the schooling age yet. Sometimes I need a marrow extraction – or, in this case, a bone sample – during the day." He chuckled a little. "I suppose, however, that in this case, it was something of an error on my part – I was too eager. I meant to inform you of what I would be doing and take the bone sample after school, or perhaps even on the weekend, so that you might be there to keep him from crying, but I misjudged the urgency of it."

Sans took two things from this statement. The first was that Papyrus had cried. Of course he had – he was only three and a half, and having a piece of bone carved right out of your arm hurt like hell. Sans knew that well. It went without saying. He supposed Papyrus was too little to have learned about holding back his screams yet.

As for the second…

"You do tests on him because I'm at school?"

"Well, technically. In many cases. Yes."

"And… you're gonna do more to him?"

"Inevitably."

"Because I'm at school."

"Oftentimes, yes. I believe we have established that."

Sans thought. "So me being at school's inconvenient. Even if, even if you need to do experiments on him, or take samples that aren't, uh, infected with DT, I could be there to keep him from crying."

Gaster hummed his agreement. "If your brother did not throw such a fit as he did, it would be easier on all of us. It can be most distracting."

Now Sans' mind was really reeling, his head spinning. "What if I didn't go to school?" he blurted.

Gaster nearly choked on his coffee. "Pardon?"

"What if I didn't go to school? I mean, I don't really need to. You said it yourself that I'm… that I'm brilliant. I already know everythin' that they could ever teach us, right? I mean, you said I'm advanced for my age and stuff. The things we're learning in math and science now, I had down when I was four. I know how to read and write. And anythin' about history you might want me to know I can learn way easier by myself with a book. So what am I even goin' to school for? 's just a formality."

He closed his eyes. "If I didn't go to school… then I could be here for you. I could be there for Papyrus so he don't cry, and whenever you needed samples, you could do whatever the hell you wanted with me instead o' him. Whenever you need me, for whatever experiment you want. And… and we could prob'ly do twice as much with the DT trials."

The silence was palpable.

After what could have been a period of one minute or ten, Sans cracked open his good eye. Gaster was watching him, fingers laced together and elbows resting on the table. He seemed to be deep in thought.

"You would be willing to simply – drop out of school to be readily available for experiments in which I would not have been able to use you otherwise due to your absence?"

Sans opened the other eye. "… yeah. Yes."

"And undergo twice as many administrations of Determination each week? Despite the fact that you realise this would come at a great cost to your own comfort, that the trials are likely to become increasingly painful? You complain of the pain regularly, after all." This seemed to be more interesting to Gaster. Dammit.

"They woulda become 'increasingly painful' anyway, doesn't make much difference," Sans muttered, then caught Gaster's eye. "Yes."

Gaster stood. He'd finished his coffee. "You are correct. You hardly need the Underground's near-useless education system. You are brilliant beyond imagination."

A tiny flame of pride sputtered to life in Sans' chest at those words. He tried and failed to ignore it.

"Very well. I shall make arrangements with your school to pull you out, under the guise of homeschooling. Your math tests with continue, of course. It is not such a bad description, really, and that you should be homeschooled will not raise suspicions, given your regular illnesses." He began to walk out of the kitchen, but stopped just before exiting into the hall. "This is excellent, Sans. I believe… only good things can come of this. For the both of us."

He was gone then, and Sans was left to sit by himself at the kitchen table, his empty glass of milk in front of him, a small and lonely thing.