Gaster Blaster Transformation Oneshots (ON HIATUS)

Not-So-Sweet 16 (🧡30k Read Special!💛)

   So semi-recently, this book hit 30k reads...
   And a lot of you wanted to see something with one of my OCs...
   Soooo... You guys get a backstory oneshot for my new OC, Flynt!
By the time this is posted, I should have all his info posted in my OC book, if you wish to know more about him.
   Image above was (obviously) drawn by me!
Enjoy! And thank you guys so much for 30k reads! 💙💚
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Flynt awoke to a slight burning sensation in his chest.
At first, he passed it off to be a weird, early-morning wake up thing, as he'd been doing quite often in recent times. It wasn't unusual to feel this way. He'd felt like this for several weeks now, but he didn't have the courage to tell anyone about it.
He sighed, half-rolling out of bed and staggering to his feet with a quiet groan. Within moments, the feeling subsided, leaving only a dull ache at the core of his ribcage. It was good enough.
Today was his 16th birthday. Already meant to be a unforgettable experience, but little did he know that it would become much, much more than that.

   The day went by, and all was going well. That is, until he went out with his friends to Grillby's. They had just gotten their food when the pain began to rise up in his chest, starting as a slight burn before it rapidly progressed to a sharper pain.
He tried like hell to ignore it, but it continued to get worse and worse with the more he tried to do so. It eventually got so bad that he had to leave. He knew something wasn't right, and he didn't want to worry, or possibly endanger everyone at the diner as a result.
   He abruptly stood up from his corner seat in the booth, nudging the black-and-silver tabby cat monster on his right side a few times. "H-Hey Coal? C-Can you get out for a sec? I forgot about something I was s'posed to do at home..."
   Coal gave him a look of both confusion and concern, but he nodded regardless. "Okay dude. Just make it quick. You still gotta open your gifts, and eat cake!"
   Flynt gave a half-hearted chuckle as the feline slid out of the booth, letting him out. "I'll be as fast as possible, don't worry."
   He speed-walked out of the restaurant, then took off running in the direction of the forest once he was outside. The pain was getting worse, progressing into a harsh cramping feeling in his bones. He was amazed that he was still able to keep running.
   He couldn't even tell where he was by the time he collapsed, landing on his belly in the soft, powdery snow.
   His hood flipped down, covering his skull with the pale grey fur lining as he began to tear up, the pain inside becoming unbearable. His body was shuddering violently, and his breathing was beginning to escalate as an irrational sense of panic washed over him.
   The young skeleton curled in on himself with a soft groan, tightly hugging his midsection with one arm while the other remained sprawled out in front of him. He felt like he was about to puke.
"C-Come on dude... D-Deep breaths..." Flynt mumbled to himself, trying to centre his scattered thoughts for just one moment.
The pain suddenly struck once again with a sharp jolt through his arms, causing him to let out a grunt in response. The source of the pain was at the tips of his fingers, and it didn't take long for him to figure out why as he heard a loud cracking sound.
His head shot up, and his gaze darted to his hand, his eyes going wide as he noticed that it was beginning to change.
   He felt his soul skip a beat as sharp points began to form at the very tips of his fingers, slowly becoming more and more noticeable with the longer he stared.
What's happening to me?!?
He gritted his teeth as pain ripped through him, causing his body to go rigid. He panted heavily, his arm still firmly wrapped around his ribcage. Sweat was pouring from his skull, mixing with his tears as it dripped onto the ground beneath him.
   The skeleton shuddered as he heard the sickening sound of bones cracking once more, at the same moment he felt his vertebrae beginning to pop and shift out of place. The fabric of his ash-grey jacket felt like it was getting tighter, and his bones felt like they were pressing against it more than they should.
   Slowly, Flynt managed to pull himself into a sitting position, and he shakily reached up, feeling across his chest first before doing anything. He was horrified when his fears were confirmed by the fact that his ribs were seemingly jutting out beneath the cloth.
   He was set into a mode of pure panic when he felt the pain beginning to rise up again, and he frantically tugged on the zipper, unzipping his beloved jacket and shaking it from his shoulders in just enough time to save it from being damaged.
The skeleton cried out suddenly as a sharp wave of pain jolted through his spine, his entire body spasming with the amount of force it took for his spine to completely reset. The agony was so bad that he could barely breathe.
   His soul pounded frantically against his sternum as he felt something beginning to protrude along his vertebrae, the fabric of his undershirt stretching out as a ridge formed down his back. He curled in on himself, biting back a scream as his shirt tore, and a row of massive spikes emerged from his now-distended spine.
He groaned hoarsely as the pain continued to ripple through him, his bones feeling more and more cramped as the seconds ticked by. It almost felt a bit claustrophobic; like his body wasn't nearly big enough to keep all the energy building up within him contained.
   The young skeleton dug his claws into the sides of his ribcage, dragging them along the bone, wincing as his newly-formed talons left huge gouges in his ribs. He felt blood beginning to trickle from the fresh wounds, but he didn't care.
   He continued to claw at his sides, ignoring the injuries he was inflicting on himself as he just simply focused on turning his thoughts away from the pain of the transformation, instead trying to cancel it out with more pain. It only succeeded in providing temporary relief.
He let out a shuddering gasp as the pain seemed to subside for a brief instant. He flopped over onto his back, the sensation of the cold snow against his bare back making him shiver.
   "J-Just breathe... I-I'm gonna get through th-this..." Flynt looked over at his clawed hands, clenching and unclenching his fists a few times. "Wh-Whatever this is..."
   He sighed, idly gripping the remaining fabric of his shirt as he closed his eyes. He took advantage of the temporary euphoria to catch his breath, inhaling deeply through his nose and exhaling slowly between his teeth, which, little did he know, had grown into long, sharp fangs.
"J-Just stay c-calm... F-Freaking out doesn't s-solve anything..." Flynt continued to mutter, trying his best to deny the fact that the pain was rising up inside of him again. He was unaware of the orange hue of his eyelights fading to a neon-yellow color, the frantically pulsating glow within his ribcage mimicking the same gradual color change.
His breathing became labored once more, his chest heaving with each ragged gasp that escaped him as his soul lurched within his ribcage, at the same moment that the intense pain began to pour back into the marrow of his bones.
His body became wracked with more uncontrollable shuddering, his back arching upward in a very unnatural manner and his bones rattling loudly with the violent spasms that were slowly beginning to return alongside the agony of the transformation.
   A wave of nausea overtook him as he heard the sickening sound of bones splintering once more, and he felt the structure of his legs beginning to change. His feet were elongating, the tips of his toes growing into dagger-like claws, all of which pressed up against his sneakers, which eventually burst open under the pressure of trying to keep his now-misshapen limbs covered.
   He whimpered softly, tears rolling down his cheeks from both the anguish and the fear, which were both completely overwhelming. He felt his non-existent stomach clench and seemingly flip over as he felt another lurch in his chest, the feeling much stronger than before.
   He instinctively gripped his midsection with one arm, a strained moan escaping him as he rolled over onto his side and folded in on himself, pounding his free hand against the ground repeatedly as pain surged through his body. The sounds of his bones creaking and snapping at such a painstakingly slow rate made him incredibly nauseated, to a point that he was almost certain that he was going to throw up.
   His shoulder blades began to bulge out beneath the stretched out and torn fabric of his shirt, pressing against it until the cloth finally gave, revealing even more spikes than what had initially came through.
"J-Just B R E A T H E..." Flynt's voice came out as a hoarse growl, significantly deeper in tone than it usually was. He couldn't help but shudder as he realized that he couldn't even recognize the voice as his own.
   He suddenly let out a wail as an intense wave of pain surged through him, his body beginning to violently contort as the transformation really began to take its hold.
Neon-yellow magic sparked across his bones, quickly erupting into heatless flame as his form changed rapidly now, leaving the young skeleton utterly helpless in fighting against it.
He threw his head back, his eyes stretched wide as he screamed in anguish. There was a slight delay before his skull began to splinter and shift, his nose and mouth stretching forward into a long muzzle as horns burst out along the back of his head.
He frantically clawed at his newly-mutated skull as a large crack split his face from his nose socket to his forehead, causing him to let out another guttural shriek. The pain was unbearable.
His entire body had changed as well, his bones growing thicker and longer as his ribcage expanded, the tattered remnants of his clothing falling off the strengthened bones and becoming partially buried in the snow beneath him.
A tail had somehow formed at the base of his spine, thrashing about in the blind panic of the horrid transformation. He wasn't even aware of it. He was slowly losing himself to the influence of something that was rapidly drawing on a strength that greatly rivaled his own.
He couldn't fight it.
He had to give in. It was too much. It hurt to move. It hurt to breathe. It hurt to think.
He wasn't sure what was hurting him more; the agony of his bones snapping and reforming into something far too inhuman and beastly for him to keep control over, or the fact that he was helpless in his battle against the creature that had taken root within his mind, and even further, had transformed his body into something completely unfamiliar.
Maybe it was the flash flood of such strong negative emotions that let control slip from his desperate grasp.
All he knew was that he was scared. Scared of the irrational fury. Scared of the crippling helplessness. Scared of what lurked in the darkest corners of his mind.

...Scared of what was now firmly embedded at the very core of his soul. And he was terrified of what he had become, all over the course of such a short period of time.
He didn't even know what he was anymore.
He wasn't the same, 16-year old Flynt that had woken up that morning.
He'd become some sort of feral beast... A beast with no control... A beast that functioned only by acting upon its own primal instincts, which could seldom be suppressed, even by itself.

And that thought alone was what terrified him the most.

Woo! How do ya like that?? Cuz I tell ya what, I f*ckin LOVED writing this!!
I love writing the "first time" transformations. Cuz that's when the affected character is in a state of extreme fear and unease, being that they have no idea of what is happening to them, and it's a lot of fun trying to work with that. :3
Also, I played around with some different wording on this, and I'm happy with the result! Kudos to whoever can figure out which new details I'm referring to lmao
Anyway! Hope y'all enjoyed my 30k read special! And, until the next update, stay determined!
-Sora 🐾