Gaster Blaster Transformation Oneshots (ON HIATUS)

Unbreakable Heart

   Not a request, but I really wanted to do a oneshot with Papyrus, so here we go. :P
   Also, no regrets on that title! (i put the song above if ya wanna listen while you read. :3)
   Artwork above belongs to guppys-paw on tumblr. They unfortunately left the Undertale fandom, but their art is AMAZING!
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   Papyrus stood on the corner of the street, waiting for the light to change, giving him the signal to cross the street. It had been a few months since the barrier had been broken, and Sans's "condition" seemed to have gotten worse. Papyrus was anxious to get back home to his brother.
   He tucked his chin into his scarf, avoiding eye contact with a group of humans that passed by, whispering to each other and pointing at him. It made him feel uneasy, to say the least.
   Humans hadn't been very accepting of monsters. Honestly, who could blame them? They'd grown so used to being the dominant creatures of the surface that having an entire race just come out of nowhere must be shocking.
   "-That's that dumb skeleton I was telling you about. It's awful that he has to babysit his brother every second. I'd be so embarrassed!"
   Papyrus flinched, looking away. He leaned against the pole standing next to him, just wishing the light would change already. As much as he wanted to believe that humans could be good, if they'd just try, he was starting to lose faith.
   "-What a freak. The world would be so much better without them."
   Papyrus gritted his teeth, biting back a sharp response. His hands clenched into fists and his eye gave off a few orange sparks. He hated it when people spoke lowly of his brother.
   But then again, was it really just Sans that they were talking about?? Or just monsters in general?
   "-We should just lock 'em all up and seal 'em away. Just like it should be."
   The taller skeleton flinched. What did monsters do to deserve such horrible treatment??
   Their words stung, in ways that he couldn't even begin to put words to. It was to a point that he was beginning to feel a dull pain building up in his chest, like he was going through a literal heartache.
   "-They don't deserve the lives they were given."
   He couldn't hold it back anymore. He had to say something.
   "Listen! I am so sick of hearing your nasty words regarding us monsters!" Papyrus snarled, whipping around to face the group of humans. "We are people too, just like you!"
   One of the teenaged humans snickered. "Monsters? People?? Please. You couldn't be people if you tried. Get a life, dumb fuck."
   Papyrus felt rage boiling inside him. How dare he talk to him, the Great Papyrus, sentry of the Royal Guard, like that?!
   The skeleton clenched his fists again, but restrained from attacking as he heard his brother's voice echoing through his head.
Don't let it get to ya. They'll try to screw with your head. Mess you up pretty bad. Just don't listen. Humans are cruel, selfish creatures.
   Papyrus found himself growling under his breath.
They aren't all like Frisk. In fact, most of them are total jerks. Just don't lose it when they pick on you. That's what they want you to do.
   His eyes narrowed as he turned his back to them and started walking away, his rage still boiling up within him.
That's it. Just walk away from it. It's not worth it.
   Papyrus exhaled slowly, trying to calm down. He needed to get back to Sans, just in case something went wrong.
Before long, he found himself approaching the front door to the house. He tried to turn the doorknob, assuming Sans had been lazy, as usual, and not locked it. Much to his surprise, his brother had actually locked it for once.
   He knocked lightly on the door. "Sans? It's me, Papyrus. Could you come unlock the door?"
   There was shuffling on the other side. "Sure. But ya have to tell a knock-knock joke first."
   "No! I will not do such a thing!"
   "Fine, guess you don't wanna come in after all-"
   "Sans! I'm sick of your bullshit! Open the door!" Papyrus snapped, slamming his fist against the door.
   A sudden lightheadedness came over him, causing him to stumble and fall against the door. He felt sick. "Sans... Seriously..."
   "Bro? You okay?"
   "N-No... I really don't feel so good... Just let me in..." Papyrus replied weakly, his voice shaking.
There was more shuffling on the other side of the door. After a few seconds, the door opened slowly, causing Papyrus to fall forward. Luckily, Sans was right there to catch him before he hit the ground.
"Bro?? What's wrong??" Sans asked, a concerned gleam in his eye sockets.
"I just... feel really sick all of a sudden..." Papyrus murmured.
"Jeez bro... You're burning up... Come on, I'll help ya to the couch."
The smaller skeleton did his best to help his brother get over to the couch, considering the height difference between them. "Is it just me or does it seem like you've gotten taller? Ah, forget it. I'm probably just thinkin' too much."
"Be quiet," Papyrus hissed, holding a hand to his skull and wincing.
"I'm just tryin' ta lighten the mood. No need ta get upset-"
"It's hard enough to focus without you constantly rambling. So just shut up. Please," Papyrus retorted, his tone surprisingly bitter.
   Sans twitched slightly. Why was Papyrus acting so weird??
   "Hey, bro. You seriously need to chill out. You're just sick, that's all..." Sans trailed off as he took notice of a strange neon-orange liquid trickling from Papyrus's eye sockets.
   He chuckled, yet deep down, he was fearing the worst. "It's... just a fever... N-Nothing more..." His eye sockets dimmed.
   "S T O P  T A L K I N G ."
   Sans flinched at his brother's response. He never used that voice. Not with him, nor with anybody else.
"Bro, please. Whatever you do, stay calm. I'm telling you this for a reason," Sans insisted, his expression remaining calm, though the tone of his voice was not.
"And what reason is that? Something I don't need to know? That's everything though, isn't it?"
Sans visibly winced. Papyrus knew he had a habit of hiding things, and now he was using it against him.
The smaller skeleton took a deep breath, forcing down his emotions. "Why are you acting like this? What the hell did I do wrong?"
   "You just... grh..." Papyrus clutched his hands to his skull. "I'm just tired of babysitting you!"
   After realizing what he'd said, Papyrus flinched. Guilt instantly washed over him as Sans's grin fell completely, his eye sockets going blank.
   "Brother... I-I'm sorry... I didn't mean to..."
   "So that's how you feel, huh? Constantly babysitting me?" Sans sighed. "Well, I guess there's truth to that."
"No, brother... I-I screwed up... I didn't mean it..."
Sans looked away, a hurt look in his eyes. "No no. I get it. I'm just a burden, huh?"
"No! That came out wrong! You are not a burden!" Papyrus insisted.
Sans chuckled softly, though the tone of it sounded... empty. Emotionless. Broken. "And after all I've done..."
"Sans, I-I... agh..." Papyrus trailed off as he felt a sharp surge of pain in his chest.
Sans's attention snapped back to his brother. "Bro? You okay?"
Papyrus took a deep breath. "I really don't know..."
His skull was throbbing. He couldn't think. He could feel his soul pounding heavily within his ribcage.
Sans's expression suddenly grew fearful as his brother looked him in the eye. "O-Oh god..."
"What? What's wrong?"
Sans slowly lifted his hand and pointed to his own jaw. "Your teeth... They're sharper..."
Papyrus felt his soul skip a beat. "Wh-What do you mean?" He traced over the gaps between his teeth with his finger, his nonexistent stomach lurching as he realized that Sans was right.
   "Oh god... B-Bro... I-It's happening to you n-now... I-I don't know what to do!" Sans stammered, his voice shaking from anxiety.
   "Hey."
   Sans stopped short in his panic at the authoritative tone in his brother's voice.
   "Don't freak out. The last thing we need is for you to have a panic attack right now. Just stay calm," Papyrus murmured, resting a gloved hand on his brother's shoulder.
   Sans exhaled deeply. "Sorry... I just... don't know how to help..."
   "I'll be fine. Maybe it'll just be little changes," Papyrus said reassuringly.
   "If ya say so, bro..."
   "Trust me. I can handle-" Papyrus broke off with a grunt of pain, curling in on himself as he clutched a hand to his wrist.
   "Pap?!"
   Papyrus panted heavily, his eyes stretched wide in a mixture of fear and agony. He could feel sweat beginning to trickle down his skull. "S-Sans... It h-hurts..."
   "I know bro... Just, please... Stay with me..." Sans tried to comfort his brother, but it was difficult since he truthfully would have rather ran away at this point.
   He pushed the thought away. No. Papyrus had never left his side when he shifted. So he would make sure he'd be there for him as well. It's what brothers do, after all.
   Sans winced as he heard the sound of bones cracking, his soul lurching at the painful reminder of what he'd been through so many times.
"B-Brother... I-I'm scared..." Papyrus whimpered softly.
"I-It's gonna be okay, Pap..." Sans reassured, shuddering at the chilling sound of bones creaking and snapping.
Papyrus let out a moan of agony, lurching forward into his brother's arms. Sans hugged him tightly, tears welling up in his eyes. "I p-promise... E-Everything's gonna be just f-fine... Just h-hold onto me... I won't let you g-go..."
   Sans pressed his face into his brother's scarf, muffling his uncontrollable sobbing. "I'm s-so sorry ya h-have to go through th-this... S-Someone like you doesn't d-deserve it..."
   Papyrus huffed, wincing as the pain surged up in his chest once more. He shakily put his arms around his brother and hugged him, trying his best to comfort both Sans and himself.
   "I-It's alright... We'll make it th-through this together," Papyrus murmured encouragingly.
   "I-I know... I just... I f-feel bad for you..."
   "E-Everything will be just f-fine. I think w-we both need to c-calm down. Last thing we n-need is for us b-both to be f-freaking out."
   Sans let out a shaky breath, his grip tightening on the fabric of his brother's scarf. "I-I don't wanna lose y-you..."
   Papyrus pulled back, looking his brother in the eye. "Wh-What makes you th-think you're going to l-lose me?"
   "I-I don't want you to g-get lost in that f-feral part of your mind... I d-don't want you to e-end up like me... T-Trapped within your own p-primal thoughts..." Sans sniffled. "I-It's a f-feeling I know all too w-well..."
   "I'll be f-fine. Don't worry-" Papyrus cut off with a cry of agony, falling forward into his brother's arms once more.
   "B-Bro?? Bro s-stay with me, 'kay??"
   Papyrus was about to reassure his brother, but the only sound that came from his mouth was a moan of pain as his spine began to snap out of place.
   Sans could feel his soul pounding frantically in panic as he became aware of something pressing against his hand, which was still on his brother's back. Spikes were beginning to form along Papyrus's vertebrae, tearing through the fabric of the t-shirt the taller skeleton was wearing.
Papyrus continued to cry out in agony as the transformation affected him more and more. His legs had begun to re-structure themselves, becoming digitigrade in appearance. His feet elongated and the tips of his toes grew sharper, completely destroying his red, worn-out boots.
He finally found enough strength and free will to pull away from Sans, just before the transformation really began to take its hold.
Sans flinched with every increasingly animalistic scream that tore from Papyrus's throat, the voice that erupted from the taller skeleton barely even sounding like his usual self.
There was still a quiet echo of Papyrus's real voice beneath the loud roaring tone of the beast he was rapidly becoming. Sans found himself backing away, despite his undying love for his brother.
   Sans watched in helpless horror as his lovable "baby bro" turned into a creature much like one he knew all too well. It terrified him to think of how this could have happened to him, of all people.
   The smaller skeleton couldn't help but sob as he considered all the possibilities.
   He wasn't even aware that his brother was towering over him, concern alight in his neon-orange eyes. He hadn't even realized that the transformation had ended until Papyrus spoke.
   "Brother? What's wrong?"
   Sans flinched and looked up, tears rolling down his cheeks. "B-Bro?"
   "You seem upset. Am I freaking you out?" Papyrus asked, lowering his skull to be at eye level with his brother.
   Sans sniffled. "No... I just... I hate to see you like this. Knowing what you had to go through to get there..."
   "Hey, I'm alright now, aren't I?"
   Sans shrugged. "I guess. But still..."
   Papyrus cut him off. "Don't worry about it. I'll figure it out," He paused for a moment. "We'll figure it out. Together."
   Sans silently moved forward, wrapping his arms around Papyrus's foreleg in a hug. "I will do anything to get you back to normal. I promise."

Wow! Lucky you! You get not one, but TWO oneshots over the course of one week! :D

Okay, but seriously, I've been working on this one for a VERY long time, and I finally found inspiration to finish it up. :P

Anyway, hope you enjoyed! And for now, stay determined!
-Sora