Alphys walked out of the hospital room, her hands shaking violently as she looked over diagnostics charts, being met with a frantic and worried group.
"Well?!" Undyne asked, jumping out of the chair she had been sitting in, looking over Alphys's shoulder through the viewing window. In the dimly-lit room were Sans and Papyrus lying back in hospital beds, both unconscious. "What's wrong with them, Al?"
Alphys rubbed her face, sniffling softly. "I...it's their s-souls..." she stammered, swallowing hard. "B-both of them..their...oh god..." She sat down hard, putting the charts on the table next to her. She took a couple of deep breaths to calm herself down, sitting upright. "...Sans and Papyrus's souls...are breaking down...and...I don't know how to stop it."
Toriel gasped, covering her mouth with her hands, her legs going weak. Frisk stared between Alphys and the window, shaking their head. "...what...does that mean...?" they asked. "It...CAN be fixed, right? Right?"
Alphys shook her head, wiping at her tears. "I've never e-encountered anything l-like this before...!" she stammered. "They...Sans and P-Papyrus are...th-their souls aren't like..." Her eyes flickered around, as though wanting to tell something they had been sworn to secrecy about.
She jumped when Asgore crossed the hall in two strides and stepped in front of the window, a heavy look of regret and heartbreak on his face. "...I should have kept those journals..." he muttered softly. Toriel looked up sharply, her eyes narrowing.
"What do you mean, Asgore?" she demanded. "What do you know about this?" Her hands clenched when he remained silent. "Asgore! If you know of some way to help, you had best speak up now!"
"...it would do no good," Asgore replied. "If the journals survived...he must have hidden them away...back Underground..." Next to him, Alphys shook harder, her hands pressed to her face. "Alphys, did...he leave anything in his old lab? Anything at all that could be of use?"
Alphys shook her head, still looking stricken for more than just the brothers being incapacitated. "No...he...a-anything he DID leave...S...Sans took YEARS a-ago...!" She shook her head harder, tears streaming down her face. "I-I'm sorry, Asgore...! He...he MADE me p-promise not to say ANYTHING...!"
"What he HELL are you two TALKING about!?" Undyne shouted, looking at the absolute end of her rope. "Are you going to DO anything!? It's OBVIOUS you're both on a page WE aren't on, so what are you going to DO!?"
Asgore pressed a hand to the glass. "...Sans and Papyrus are not like other Monsters," he replied. "They weren't born...they were MADE...and to be honest, I'm surprised this hasn't happened sooner." The hand on the glass clenched into a fist. "And...the ONLY one who can do ANYTHING doesn't even EXIST anymore!"
The air suddenly became thick with a stillness that was reminiscent of time stopping, the breath of everyone catching in their chests. Everyone stood stock still, internally reeling at the sensation, breaking from their spells when Asgore let out a strangled gasp and stumbled back from the glass.
Alphys jumped up and looked into the window, letting out a yelp when inside, she saw a solid shapeless blackness flickering like an image with bad reception between the two beds. The black shape slowly shifted and stretched, three white shapes appearing in the positions of a head and two hands. It finally stopped flickering and slowly turned around, and it was Alphys's turn to jerk away from the window.
"Holy shit..." Undyne murmured, her eye wide. "...what the hell IS that thing...?!" A spear appeared in her shaking hand on reflex. Asgore dropping like a rock to his knees next to her, startling her from looking at the...thing. "...Asgore...?"
Asgore was looking as though he was seeing death itself, his hands pressed to his mouth, his breath ragged and forced. It filled Undyne with dread, seeing her former king in such a state, so TERRIFIED of this creature THAT HOLY SHIT WAS IN THE ROOM WITH SANS AND PAPYRUS!
She reared her arm back and lobbed the spear through the glass, right to the creature in the room. The creature raised a hand, the spear stopping mid-air and then vanishing into nothing.
Undyne growled, forming another spear, jumping when Alphys leaped over and forced her arm down. "Alphys, what the fu—"
"DON'T!" Alphys cried, her body shaking violently. "D-don't...p...please, Undyne..."
"Alphys, what the hell IS that thing!?" she demanded, unable to look away from the creature. If she were being generous, she would say it resembled a Skeleton with no teeth and a half-melted cracked skull. It was more the presence it gave out than the actual sight of it that unnerved her more than anything; an unnatural, tangible aura that seemed to take the air from the room, slow time to an agonized crawl...
"...he's alive..."
Asgore's voice broke Undyne's gaze from the creature, turning to see Asgore silently crying, that horrified stricken look still on his face. Next to her, Alphys had a similar expression, looking just as ill with terror.
"...I w-watched him d-die though...!" Alphys whimpered, her eyes flicking around, not wanting to settle on the creature. "I...I SAW h-him...!"
Toriel was shielding Frisk behind her, also unable to look away from the being in the room, torn between staying back out of fear and wanting to run in and snatch Sans away from it. The effect this creature was having on ASGORE told her that this was not something to be trifled with, but Alphys's insistence at it not being harmed was another matter entirely. "Asgore..Alphys...who...or WHAT...is that...!?" she demanded.
"...T...Tori..." Asgore stammered, clenching his eyes shut. "...it's Gaster..."
Toriel's heart dropped to her stomach, feeling an icy cold grip her body. Gaster? Dr. Wingdings Gaster?! It COULDN'T be! He died years ago! What was he doing HERE!?
Gaster turned back to the two younger Skeletons on the hospital beds, his warped expression still able to convey pain and despair. Even now in this happiest of times, his sins were still being taken out on his sons, the distance he put between them for their sake only tearing their souls apart in a bid to return to their source in the Void.
It would be so easy...to take them back with him. To bring them into the Void so they could be together again. But he was done being selfish, no matter how good his intentions. His children had lives, loves, friends, hopes, and dreams, and he would be the foulest creature in the multiverse if he took that away from them now.
That only left one option.
He raised his hands, hovering them over the boys' rib cages, summoning forth their souls. The soft magical glows—blue for Sans's and orange for Papyrus's—were but a dying flicker, the portions of the souls that had grown and developed on their own slowly chipping away into something almost unrecognizable.
Gaster brought his hands to his chest, summoning forth his own soul, a pitiful, twisted thing coated and stitched together with an inky blackness that didn't look like a soul at all, just an ethereal THING that made up his sad existence. But this pitiful thing would be the final salvation, the missing piece to their souls that would anchor them as true Monsters and not just lab experiments, not just sentient clones.
He took the soul in his hands, clasping it tightly before snapping it in two.
Alphys had to forcefully hold Undyne back when Gaster summoned the Skeleton brothers' souls forth. "Undyne, STOP!" she cried. "He...he won't hurt them! He...he w-WOULDN'T...!" She buried her face into her girlfriend's abdomen, sobbing. "P-please, he's their f-father...!"
Undyne's body froze, a painful throb in the back of her mind shooting forth like a migraine, images of her childhood flashing before her, painful images she buried away because they were times before her mother's passing.
Images of a baby bones peering over the edge of a fountain and smiling at her.
Images of splashing around, finally happy at having someone to play with.
Images of a tall, dark figure picking up her new friend.
Images of the figure returning, again and again with her friend, always within view, watching with pitch black eye sockets that seemed empty when her friend's somehow seemed so warm and happy, but never being afraid of him because...
...That's Papyrus's daddy.
Undyne looked up sharply, seeing Gaster pull a twisted, wretched-looking soul out of his body, holding it in his hands before breaking it in two, a sharp ripple snapping through the air. Undyne flinched hard, curling her arms around Alphys, almost feeling a similar snap in her own soul by empathy, shaking hard as Gaster lowered the halves of his soul to the waiting souls of Sans and Papyrus.
For a moment, nothing happened.
And then an inferno of magic energy exploded in the room.
