Sans was really starting to hate being strapped to chairs.

He watched his father carefully as the tall man muttered to himself, carefully measuring out a sample of that godforsaken red liquid. Artificial determination, Gaster had called it, back when he first told Sans about the experiment. It was supposed to boost the immune system, allow one to heal faster and become more resilient to physical harm.

It was supposed to help people.

At first, Sans was hesitant. Of course he was - who wouldn't be a bit wary of a new, relatively untested and dubiously stable substance entering their bloodstream? Gaster was persistent though, always quick to remind his son of how vital his participation in the project would be, of how on top of saving lives he wanted to improve Sans's health, to make him stronger.

Sans always had been a pretty weak kid. It was almost laughable, how fragile he really was. A mild case of osteogenesis imperfecta and an immunodeficiency disorder left him short-statured and worryingly prone to illness and injury. However nervous the prospect of this new drug made him, the thought of being bedridden more often than not for the rest of his life scared him more.

In the end, it didn't take much to convince him to be the first human test subject of Gaster's life's work. The idea of a more normal life paired with his father's constant reassurance and promises actually made everything sound pretty enticing.

The doctor bent over his son, cleaning his upper arm with a cold sanitary wipe. Sans could feel his heart pounding, and it was everything he could do to keep himself from shaking. He had only been strapped down for an injection once before. The first injection.

That first one had been the worst, no doubt about it. While the subsequent doses had all been delivered via veins in his arm, the initial injection was different. Gaster had mentioned something about lobotomies as he gently secured the straps against Sans's wrists. Apparently the doctors back then had something right - it was the easiest way to access the brain.

Sans tried not to think about it now, but it was hard to forget when his eye began to throb. That was the first time he had truly feared his father.

Finally, Gaster brought the needle over. Despite his reservations, Sans glanced at it. He immediately wished he hadn't. The syringe was distinctly larger than any they had used in the past, and it was almost completely filled. Gaster said nothing as he pushed the substance into his son.

This had been routine for over three years. Every week, then every other day, then daily, Sans would receive a dose of this "artificial determination." It hurt every time, but eventually it became a familiar pain.

Today, though, something was different. The first few seconds, everything was normal, just like yesterday and the day before. Then it hit, all at once.

Sans squeezed his eyes shut and bit his tongue, doing everything in his power not to cry out. He hadn't screamed during an injection in years.

The pain kept building. It burned, more than it ever had before. Sans could feel it slicing into him, like it was tearing into each cell and ripping apart his very DNA.

"Ngh-" he clamped his mouth shut, breathing rapidly as pressure built up in his head and his body began to writhe.

"Gaster, p-please, it hurts, Dad, please, help me!" There wasn't any sign of respite, and though his eyes were shut, colors swam in front of Sans's eyes. He couldn't think, couldn't breathe.

Gaster watched his son contort in agony, a troubled expression on his face. There was nothing he could do, though. Nothing but remove the straps after Sans finally blacked out.

To be honest, Sans probably shouldn't have driven to school the next morning, or gone to school at all. His vision was blurring in and out of focus, he was nauseous, his hands were shaking, and he kind of felt like he had been hit by a truck. Papyrus certainly had been confused by his brother's odd behavior, but a half-hearted joke about needing to exercise more had set him at ease, at least a bit.

Well, he was here already. Might as well get on with it.

The noise hit him right when he walked through the doors. There were students everywhere, talking to their friends as they waited for the day to begin, and it was so, so bright. Sans briefly wondered if this was what a hangover was like.

"Hey, Sans! Did you and Grillby really skip yesterday? Ha! I didn't think you had it in you!"

Ugh. Sans loved Udaya, he really did, but her yelling wasn't doing any favors for the pounding in his head. He gave her a small smile and walked over to where she, Alice, and Grillby were sitting.

Udaya frowned at him. "Dude, you look like shit." Alice nudged her.

"I'm fine, just didn't sleep well last night," Sans murmured. He glanced at Grillby, who was looking at him in concern. It seemed to be a common expression nowadays. The taller teen stood up and placed a hand on his forehead. Sans went to pull away, but his body betrayed him and he leaned into the touch. Damn it.

This felt nice, though. It wasn't quite holding hands, but it was something.

"Sans, you're burning up," he said softly. "Why did you even come in?"

He shrugged, hating the worry in Grillby's voice. "Don't feel that bad."

Grillby sighed. "Somehow I don't believe you. C'mon, let's go to the nurse."

Feeling too dazed to protest, Sans allowed his friend to help him stand and lead him to the office. He vaguely registered Alice and Udaya telling him to feel better, but mostly he just focused on walking without stumbling.

"Sorry," he muttered. "You don't… you should get to class. I'm okay."

"Class won't start for another 10 minutes, anyway. Besides, you're more important," Grillby said without hesitation.

They arrived at the nurse's office before Sans could think of a response. He took one look at Sans and told him to go home, not even bothering to check his temperature.

"Looks like you've got the flu. It's been going around. I'll let the office know you'll be out sick today - is there someone that can pick you up?" the nurse asked.

Sans squinted at him. "No?"

"I can take him," said Grillby. "The bell hasn't rung yet, so I won't need to sign out or anything."

The guilt was enough to make him wince. They had already skipped class yesterday, and though Grillby had agreed to it, Sans was the one to suggest it in the first place. Now his friend was going to be late because of him.

"You- you really don't need to do that, G. I drove here, so I can drive back home. It'll be fine."

The nurse looked at him sternly. "You're not driving, young man, not in this condition." He addressed Grillby. "Tell you what, I'll see what I can do about getting you an excused tardy, just try to get back as soon as you can."

"Thank you, sir." With that, Grillby gently pulled on Sans's arm, leading him out the doors.

It was bright outside, the sun glinting off the snow with a vengeance. The two teens walked slowly to the parking lot, both grimacing at the sudden light.

"Man, this hit you pretty hard. Were you feeling okay yesterday?" Grillby frowned as he thought back to the afternoon they had spent together. His friend hadn't seemed ill then, but…

"Heh, yeah, it's uh, kinda weird. I felt fine yesterday…" until last night, of course, but Grillby didn't need to know that.

They climbed into the car Grillby shared with his mom, Sans relieved to sit down again. It was strange, really, how much this particular increase was affecting him. The more recent times Gaster had upped the dose did wear him down a bit more than they used to, but yesterday's injection really had him down for the count.

As they pulled out onto the road, Grillby glanced at his passenger. He really did look awful, cheeks flushed, eyes half-lidded, the whole works. The lack of puns was more concerning than he wanted to admit.

"Are you going to be alright?"

Sans turned to look at him, a lopsided grin on his face. "I'll be fine, Grillbz, you don't gotta worry about it. It's just- just the flu. Nothing that hasn't happened before." Well, that was true in some sense. He and influenza were well-acquainted as kids, and this was almost the same thing. Almost.

Grillby smiled back at him. "Yeah, I know. Sorry for nagging."

"This is nagging? Really? You should hear Papyrus when he catches me being lazy. This is nothing."

That got a laugh. Good, that must mean he at least sounded coherent.

The rest of the trip was peaceful, and Sans couldn't be more grateful for Grillby's cautious driving. Sharp turns and jerking didn't sound like something his stomach could take at the moment. He could feel his eyelids drooping, but didn't realize he had shut them until Grillby spoke again.

"Hey, we're here," he said softly. Sans slowly blinked awake, looking around in mild confusion.

"Oh, heh, sorry." He climbed out of the car, automatically reaching to grab his bag. Wait, did he leave it at home this morning?

"You didn't have your bag with you when you got to school, if that's what you're looking for."

Ah. Grillby was so observant. And patient. And-

"Thanks, G. For… all this." He didn't have the energy to say more, or make a joke. He thought Grillby understood anyway.

"Of course, Sans. Go get some rest, yeah? And don't come to school tomorrow if you're not feeling better."

Sans chuckled a bit, stepping fully out of the car. "Gotcha. See ya later."

Grillby stayed in the driveway until Sans made it inside the house. He smiled to himself as he watched the other pull away. What a mother hen.

After grabbing a bucket from under the sink in case he actually did puke, Sans slowly walked to his room. His car was still at the school… shit. Gaster had been coming home late for the past week or so, and he didn't usually answer his phone while at work anyway. Papyrus needed a ride home from school.

Damn it.

With a sigh, he sat down on the bed and pulled his phone out, finding Grillby's name in his short list of contacts. He picked up on the first ring.

"Sans? Is everything okay?"

"Ah, I have a favor to ask, actually. I'm really sorry about this, I know I just made you late to-"

"Sans. Shut up. What do you need?"

Man, Grillby was too good to him.

"I usually bring Papyrus home, but my car's still at school and Dad's not going to be home until late… would you maybe be able to pick him up? I totally get it if you're too busy, or you don't want to, I can figure something out, I probably should have just-"

"I remember where we picked him up last time, it won't be a problem. Will he be okay with someone different? Should I call the elementary school to let him know ahead of time or something?"

Way, way too good to him.

"Nah, he'll be fine. He really likes you. Thank you so much, Grillby, I really appreciate it."

"Don't worry about it, he's a great kid. It'll be nice to hang out with him for a bit. Go to sleep now, okay?"

"You're the best, G."

He was asleep in less than a minute.

Sans really, really hated being strapped to chairs. There was a loud ringing in his head, and he couldn't seem to focus right. The room he was in was distorted by static, and everything seemed… dark.

Really dark.

A sharp noise sounded on his right, and Sans felt his head loll over to look.

Gaster was standing there, staring down at him. Smiling.

Twin cracks ran down his face.

Sans tried to speak, but no words came out. He tried to move, but he was stuck.

The darkness was growing.

The scientist was saying something, but Sans couldn't understand. His voice was garbled, almost like he was speaking in some strange new language.

The shadows were cutting deeper.

He lifted his hand. Plunged the needle he was holding into his son's chest.

Sans couldn't even scream. He watched, terrified, as burning pain spread throughout his body.

His body…

Something was wrong with it.

His legs. They felt…

They were melting.

His skin was melting, then dissolving into dust, leaving behind nothing but bones.

The sensation worked its way up his legs, through his torso and arms and eventually to his head.

Soon it was all gone.

Nothing but bones.

Sans screamed.

"Do you want to come inside?"

Holding the door open, Papyrus looked expectantly at his companion. Grillby hesitated, not wanting to intrude, but he had been hoping to check up on Sans…

"Is that okay with you? I'll only stay for a few minutes."

Papyrus beamed at him and they walked in. He began taking off his shoes, but paused when he heard a noise coming from the bathroom.

"Sans?" He looked up at Grillby. "You said he didn't feel good?"

The taller of the pair nodded, brow furrowing worriedly as he peered into the hall.

"What if I go check on him and you make that tea you were telling me about? I think your brother would really appreciate it, especially coming from you."

Papyrus debated with himself. He wanted to comfort his brother, but he never really knew how to help him when he was sick. The tea always seemed to make him feel better, though. Would Sans be okay if Papyrus didn't go to him immediately? Well, Grillby was here at least…

"Okay," he whispered, taking his other shoe off and heading into the kitchen.

Grillby didn't waste any time, quickly heading towards the bathroom.

"Sans?" he knocked quietly on the door. "It's Grillby. Can I come in?"

There was no reply. Worry building, Grillby opened the door.

The older Roman sibling was curled around the toilet, wrapped in a blanket. He was shivering, face glistening with sweat and tears. Grillby kneeled in front of him, placing a hand on his forehead. Sans looked at him, eyes slightly glazed.

"...G?"

"Yeah, it's me." He bit his lip, not sure what else to say. This was the most vulnerable Grillby had ever seen his friend, and he wanted nothing more than to pull him into a hug and tell him everything was going to be okay. He settled on brushing the hair out of his face.

Sans shuddered, a few more tears dripping down his cheeks.

"S-Sorry."

"Shh, none of that. Do you think you can go back to bed, or do you need to stay here?"

In response, Sans shifted, sluggishly attempting to lift himself up. Grillby was quick to help him, and the two slowly made their way back to Sans's room.

Papyrus came in just after his brother had gotten settled under the covers, and Sans visibly relaxed at seeing the younger.

"I-I made you some tea." He cradled the mug in both hands, walking carefully over to the bed.

Sans smiled at him, wiping his face. "Thanks, bud. I feel better already." He took a small sip of the tea and set it on the nightstand.

"I thought you were done getting sick like this!" Papyrus blurted out. His bottom lip quivered as he took in his brother's state.

"I'm okay Paps, jus' the flu."

The fourth grader sniffled a bit, then nodded, still looking upset. Sans reached out and squeezed his hand before turning back to Grillby, who spoke before he could even open his mouth.

"You're welcome, Sans, and don't even think about apologizing."

The shorter teen grinned. "Y'know me too well." He breathed in deeply. "I think 'm ready for another nap, and Ga-" he made a subtle face. "Dad should be home in a coupla hours." Even as he said it he was beginning to nod off, the terror from earlier subsiding.

"I guess I should get going then," Grillby said. "Let me know if you need anything, both of you." He sent what he hoped was a comforting smile to Papyrus, who gave a small wave back. It seemed Sans had already fallen asleep.

With one last look back, Grillby left the room, trying and failing to suppress the concern that was sure to plague him all night.

"Feel better, Sans."

Whew! We're getting close to the climax, guys! Just you wait ;)

So, I've actually been thinking pretty seriously about writing a sequel after this is finished... would anyone be interested in reading more? I think there's definitely room for development with these characters.

That being said, I hope you enjoyed Chapter 11! See you all soon.