Sans looked down at the writhing child coldly, stepping closer only to land a hard kick into Frisk's stomach. The wound was large in scale; it consumed their little body and blood pooled beneath them, staining their clothes. The stench of iron and salt was thick in the air and Sans revelled in it; his grin just seemed to stretch and grow with the pain the evil urchin endured. It was never in his nature to enjoy another's suffering, but this case was an exception... This little beast killed his brother.

They should be burning in hell on a day like this.

Frisk continued to feebly gasp and strain to live, even when there was no chance of that happening. Sans couldn't bring himself to tame his smile, if only momentarily. "That's what you get, you dirty brother killer..." He knew that Papyrus would not approve of this sociopathic behaviour. But he was no longer here to hold Sans back. As he addressed the child, there was hatred in their eyes and it spewed from their mouth as incoherent sentences. He wondered, amused, what had made such an evil monster. Frisk had been out to kill, both innocent and guilty, and came out of it with blood on their hands. Sans did a double take as he noticed the blood on his own hands (and torso) but his mind immediately justified it. This little beast deserved the longest, most painful death one could ever imagine... For a reason that perturbed him, Sans actually felt glee watching the blood pool and Frisk's eyes grow dull.

In fact, it was the dullness that snapped him out of it—and heard a distinct, gleeful voice egging him on to kill Frisk. Sans blinked, eyes fixated on Frisk's. It was strange to look at. Their eyes were crisp and clear like the air of an autumn day, sober. This was very unlike their usual, empty gaze—this time, they silently begged for him to run. Just as he noticed the peculiar expression, the voice in his ear hissed in annoyance. "Just hurry up and kill them! They aren't of use to anyone at all anymore." Sans whipped his head to the right and spotted a faintly glowing soul hovering above his shoulder—which flinched back at the intensity of his glower.

"You..." Sans hissed.

And in an instant, it clicked.

This soul had been possessing Frisk during their genocide run. And now that Frisk was near death, it had abandoned the child in place for a new host.

In an instant, the world came crashing down on him. Chills of horror crawled up his spine as Sans realized just what he had done. The gleeful glow of the electric blue light ceased and he stood, looking down at the near-death Frisk, too numb to say anything. Toriel, Papyrus, millions of innocent creatures. He hadn't gotten justice for them. No... Frisk wasn't responsible for their actions...

His head took another sharp turn, with the fire in Sans' eye reignited, "You are." He snarled at the stray, malevolent voice that had done this to Frisk. To Pap and to Tori. The soul merely giggled in glee at the range of fury in his eyes, dancing around him without a care in the world.

"Go on, try it," Chara taunted him. "C'mon, give your skeleton friends a go at me. I dare you." With the rage pummelling through his veins, he very well could have killed the little soul. But with Frisk needing attending to, he had no time or patience to handle this monster. The small skeleton drew in a steady breath, trying to regain control of his fiery senses. The long corridors seemed to echo every sound he made, even the slightest; Sans rose a skeleton hand and summoned ten of his little "pals" with a flash of brilliant blue light.

While the halls flooded with a blinding glare, he heard Frisk whimper softly, blood gently trickling from their lips. His bones felt chilled at the prospect of hurting an innocent, but he knew that, to some degree, Frisk was also at fault. The sympathy for this pathetic form faded, albeit slowly... the flames in his eyes, redirected at Chara's grinning translucent face, fixed the skeletal heads to surround her without a word needing to be spoken. The air, though deathly silent and cold, was also so thick that a butter knife would easily sever it. He could feel the cool waves of energy flowing from Chara's soul, smell the burnt air and tasted her acidic spirit.

With one last cold look to Chara, who seemed daintily preoccupied with the skeleton heads for one reason or another, Sans slowly began to move towards Frisk, inching his way over, before his patience wore thin and the panic flooded back—he broke into a run, skidding over to Frisk's little human body. Unsure of how to act (he wanted to hold them, but he feared he would hurt them even more,) he gently whispered to their ear, brushing his bone fingers through their messy hair. "Frisk, buddy. C'mon, wake up," Sans begged. "I'm sorry buddy. I'm sorry. Please wake up." When they failed to respond, Sans wriggled out of his navy blue jacket and gently wrapped them in it (like a burrito, he dully joked.)He held them close to his chest as he sat, the flames in his eyes gently taking on a more nurturing colour of a pastel pink. His forced smile seemed to waver when Chara's voice came from behind him, spitting profanities.

"I guess it really wasn't you doing this..." Sans' eyes floated to the gaseous form of an angry red that Chara's body had become. "Was it... Frisk...?" The entire corridor was now swarming in this fog, and the throbbing energy seemed to drift off her in a contagious hatred. He felt the burning in his bones, and retreated his skeletal monstrosities. This was something... he wanted to do on his own.

He glanced down at Frisk, weakened and blood trickling from their mouth, and felt his stomach twist up in pain and nausea. I enjoyed this, Sans thought feebly. His reached out his bony hand to touch Frisk's (likely concussed) head, but jerked it back instinctively, unable to bring himself to even brush their hair again after when he had done to them. There was sweat forming beads on his forehead. "Ah, geez kid..." Sans 'whimspered'. His eyes were gaunt with indescribable pain; his arms began to tremble lightly. He forced a smile, as if to reassure them. But was it him he was trying to reassure? "Heh..." He laughed uncomfortably, "really, uh, banged you up..." their lack of response was like a punch in the gut.

"H-hang in there, kiddo," Sans murmured, though he felt as though he were begging—begging for forgiveness, or for Frisk to just wait a little longer? He could save them... but... he'd need Alphys... Who would want to help the kid after what they appeared to have done? No one would be willing to believe his story—even if he was a generally trustable monster.

The very thought of Frisk dying—because of him—made him want to keel over and spill his stomach contents. He would never be able to live down this guilt. He gazed at the kid, unable to keep his hand away any longer. He brushed their cheek, the blood smearing on his hands. "Oh God." He spoke hoarsely, "o-oh my God." The guilt seemed to set in even stronger than before, and the sickness in his stomach was growing. "I—I'm sorry. What have I done to you?" As much as he felt disgust with himself, Chara's giggling seemed to coax the feeling towards her instead.

"You've killed them, Sans~~!" Chara sang softly, taking glee in his emotional trauma. "You're just like me!"

He felt Frisk's pulse from their neck; as much as they were alive, he panicked when their pulse appeared weak and struggling. How it didn't stop yet was beyond him, but... Determination. They—they heard my voice! They're hanging onto life as much as they can! Sans realized. As if in an uncontrollable insanity at the scare he had, he began to giggle. "Heheh... I-I shoulda..." His eyes widened. "Chara..."

In a split second, all hell broke loose.

"YOU'RE GONNA HAVE A BAD TIME, CHARA."

Frisk's hand slowly moved on his chest, as if to keep him relaxed. He looked down at them, determined to end this ordeal. Gently, he placed Frisk on the cold tiles of the corridor floors. "J-just rest here, kiddo," Sans murmured. He smiled weakly at the next part, "Dad's gotta... dunk someone." Sunlight struck their body in a way that seemed to embrace the scars and crusted blood on their face, making Sans nauseous once more. He kneeled over top of them, eye ablaze in an electric blue. "God... look at you, bruised left and right..." He narrowed his eyes. "Don't worry. After this, we're gettin' out."

He turned his head slowly, as he stood. He snarled. "As for you, Chara..."

He took one more step towards the foggy ghost, and his fists caught on the same cerulean fire as his eye.

He smirked, feeling Frisk's determination flow through him.

" T-i-m-e-t-o-g-e-t-D-U-N-K-E-D."

Disclaimer: I don't own Undertale. But I do own this story.

AN: My name is Haze Spawn! This story is based on one of my comics found on Deviantart which you can find here. This is a one-shot, meaning that I will not continue this story, as I feel it's ended fine without needing more closure. Anyway, I hope you enjoyed this read! Have a wonderful day!

Ps: If anyone is wondering, this story was supposed to be like another option in the genocide route. Like after he dunks you, this happens.