It takes him an embarrassing amount of time to realize Sans is even in the room with him.
In his defense, though, the lights are off, it’s three in the morning, and his brother is huddled motionless at the foot of the stairs, eyelights dimmed to nothing. If he's shaking—he’s usually shaking—he’s quieter about it than usual, no rattle of nervous bones that Papyrus can hear until he’s snagging his foot on Sans’ femur and pitching forwards over his brother’s stunted, snarled-up body.
“Shit!” he hisses, barely catching himself on the railing before he loses his footing entirely. He whips around, angles a glare down to somewhere around his kneecaps where Sans…well, he doesn’t cringe at the sound of his voice, exactly, but it’s a near-miss. Aside from the panicked rise-fall-rise of his shoulder blades, he doesn’t move. “What are you doing?” Papyrus asks after a handful of long seconds, when it’s clear his brother has no explanation forthcoming.
Sans doesn’t look at him. Sans doesn’t look at anything, but he answers, dutifully, quietly, “waiting.” The tip of his tail thumps against the carpet only once, and stills. He’s damp, kind of, like he’s been out in the snow, but that can’t be right. Dad has been in the basement since eight this morning, and Sans isn’t exactly prone to wandering off on his own.
Papyrus frowns. “Waiting for—?”
The basement doorknob twists open and Sans gives this low, horrified keening sound Papyrus is sure he wasn’t meant to hear.
“S4,” his father says mildly, only it’s pitched just too low, just too even, just shy of casual. That’s…probably not good. At his feet, Sans’ entire body tenses up like Gaster’s pulled tight on the leash he isn't wearing, claws curling deep into the cotton of his hoodie. “I’m fairly sure you know what I’m about to ask.”
Papyrus looks down at his brother, puzzled, but Sans is already nodding his head jerkily. “yessir,” he manages, barely audible.
Gaster tilts his head to the side and studies his creation curiously, eyes narrowed. “Would you like to tell me about it on your own, or shall we start with the phone call I just received from Rebecca’s mother? Papyrus, it might be best if you returned to your room. We can discuss what happened to your eye later.”
At the mention of Becky, Papyrus blinks. Why would her mother call? Surely the girl didn’t want to apologize, she’d made it pretty clear earlier that afternoon, when she’d ground Papyrus into the playground dirt, one paw planted firmly on the back of his skull. He can still feel the gritty bits of soil between his pointed teeth, actually, the taste heavy and metallic on his tongue. And you know what, how dare she, how dare she lay her hands on him, that little bitch, he’d skin her alive next time they saw each other, he’d tear her ears off and choke her with them, he’d—
“Why’d Becky’s mom call?” he asks, half because he’s curious, half to interrupt his own brain before it spirals any further off-track. He's already picturing blood splashed bright on new snow, though, so it might be too late for that already.
“Something to do with the mess her daughter made of your face, I expect,” Gaster replies, not unkindly, but Papyrus drops his gaze to the carpet anyways. “She was much more concerned, however, about the fact that my other son,” he spits, and Sans whimpers like he’s been kicked, “paid her daughters a visit this afternoon. Broke three of the older girl’s ribs, she said.”
Papyrus gapes down at his older brother. He—okay, fine, he knew Sans wasn’t exactly thrilled with the way he was treated at school, disliked it enough to voice an actual opinion on the matter, which happened only a handful of times that he can even recall, but…he’d never even seen his brother fight, not for real, much less seen him fight a ten-year-old child. “What is he talking about?” he asks, shakily. “I told you—I told you to stay out of it, didn’t I? What the fuck were you thinking?”
“Yes,” Gaster says. “You told him. And look how well that’s turned out! You coddle him far too much, Papyrus—he’s becoming a liability. He could have easily killed that girl.”
Sans seemingly has nothing to offer in his own defense, but he’s pushed himself against Papyrus’s shins as though he thinks it might shield him from his pseudo-father’s rage. Papyrus doesn’t even think it’s totally conscious, the way he gravitates towards his younger brother when he’s frightened, because it doesn’t make sense—he doesn’t have his father’s streak of casual cruelty, maybe, but he’s hardly kind to Sans.
Papyrus should shove him away, should kick him over and join Gaster at the foot of the stairs. He should be proving a point here. This isn’t his fault, this doesn’t have anything to do with him anymore! He told Sans not to get involved. He tried, he really did, he tried to keep Sans out of trouble, he always tries to keep Sans out of trouble but he was always so incapable of just listening—
“But he didn’t,” Papyrus’s mouth says, mostly without his input.
Gaster blinks. “Pardon?”
“He didn’t kill her.” Sans actually looks up at him then, browbone wrinkled in confusion and Papyrus doesn’t really register that he’s reaching for his brother until he’s curling his fingers around the warm, somewhat sweaty curve of Sans’ upper cervical spine. It’s a little crooked, he notes absently. He smooths over the ridge of one vertebrae with his thumb and wonders how he never noticed.
“You could have, right? You could have dusted her right there and then. More than that—you wanted to dust her.”
Sans doesn’t say a word but he nods slowly, dragging, like he’s moving through molasses. The repetitive motion doesn’t seem to soothe him—if anything, he’s shaking harder than ever, but he doesn’t pull away from the touch. “You held back. You wanted to scare her. For me.”
“yeah,” Sans breathes, pushing up into his hand. "yeah, that’s—that's all i wanna do, Pap, she shouldn't have hit you—“
Papyrus laughs and Gaster's tilts his head to the side slowly, as though he's trying to find an angle from which this makes sense. "You wanted to kill her, though. In that moment, you actually wanted to kill a child."
Sans winces. "i-i guess."
"Papyrus, it's the middle of the night," Gaster interrupts wearily, massaging his temples with long white fingers. "Where are we going with this?"
“'Where we're going with this,’" he says with a wide grin, "is that he did exactly what you made him for, Dad. He didn't want to, he never wants to fight, but he did it! He was compelled to. For me."
Sans doesn't stop smiling—he can't, no matter how much he's hurting, Papyrus knows that all too well by now—but all other expression vanishes from his face, like someone’s pulled his plug. He looks blank. Horrified.
“I could make you do anything,” Papyrus breathes. “Couldn’t I?”
“Listen,” he insists. “You’re hardly a strategist. The king is the only reason you've made it this long without someone dusting you, and that's only because he needs your brain! We both know that, we both know you're absolute shit at fighting so shut up and listen to me. Becky kicked my ass today, okay? And how did her mom sound when you talked to her? Did she say anything about how Becky was?”
Gaster scowls, shrugs. “Said the girl was scared to death. Tried not to tell her, apparently, until the pain got so bad she passed out getting up for a drink. Lucky her sister still shares a room with her.” He shakes his head. “I can try again, Papyrus. We always knew he was a long shot. We should consider ourselves lucky he made it this far, honestly. I can make some tweaks to S5, maybe—“
“No,” Papyrus snarls.
“You’re being unreasonable.”
“You wanted an attack dog,” Papyrus says. “It’s not fair to punish him for attacking.” It doesn’t escape his notice that this time, when he reaches out to run tentative fingers over the curve of Sans’ right frontal bone, his brother screws his eyes firmly shut.