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// 5% 
// Story: Book 1 - The Behemoth came to Canterlot 
// by Equimorto 
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A dark, deep black crystal descended from the ceiling, at the tip of a metallic arm that positioned itself through the clicking gears at the junctions of its different sections. Behind the glass the unicorns watched, slight tremors wracking their bodies and expressions.
The stallion on the table still looked determined, yet his expression couldn't help but falter whenever he looked at the unicorns'. But he knew it would be safe. It had to be. He had been chosen for that role by Nightmare Moon herself, and there was no reason to hesitate. No reason to ever go against her will.
The crystal came down onto his chest, like an hammer and a nail onto a plank of wood, and no amount of loyalty or training or brainwashing could stop the scream. Beyond the glass, the male unicorn lowered his gaze, refusing to watch the stallion's face. But the other kept her eyes on him. Somebody had to, after all.
Thick black protrusions began to appear on the pony's chest, expanding outward from where the crystal lay halfway into his body. They were much like veins, only far larger, and not belonging to his old body. Like roots of something else slowly forcing itself on him, snakes crawling beneath his skin and through his flesh.
His face was distorted by agony, his eyes shot with blood and his pupils shrunk to the tiniest size. He shook, violently, but the straps around his limbs and torso held him down. Whether he was still screaming or he'd run out of air for it was a question that crossed the unicorns' mind, if not one they wanted an answer to. If anything though, he was at least still alive. Clearly, as a trained soldier, he was robust enough to take it up to that point.
The surface of his body began to shift. His hair grew darker, until it was a deep blue that could barely be told apart from black. It started in different patches at first, but soon his whole body had changed colour. His eyes were blood red at that point, dozens of vessels popping in them, and his teeth grew sharper and misshapen as they pushed against each other in a mouth too small for all of them.
The female unicorn clenched her jaw. She knew what would come next, and knew no subject had ever made it past that point. On the other side of the glass bubbles began to form on the stallion's skin, some small as an ant while others bigger than an eye. It was as if his own skin and flesh and hair had turned to tar, slowly melting as it enveloped him.
The shaking continued. The male unicorn finally looked up again, knowing the time had come, knowing from that moment onwards he would be a dead pony walking. And he watched, slack-jawed and breathless, as the bubbling on the stallion's skin stopped and the almost fluid mass around him seemed to revert in its melting process, growing stable.
The pony's limbs and body began to expand and shift. His torso shot up, burying the crystal all the way in, while his restraints snapped. Bones split and shifted in his legs as muscles wove themselves around them in new patterns, thick and outlined by the almost lucid layer of his hairless skin. His hooves broke into chunks and grew sharper, claws at the end of four-digit paws that looked more like swords than anything an animal should have.
His jaw and mouth grew wider and longer, a myriad of sharp fangs now finally free to position themselves in it. His pupils turned to slits inside red irises, below the prominent brow of his elongated face. Pushing the machine atop him aside, bending it and snapping a few cogs in the process, he stood and turned towards the glass window.
On his forehead was a small perpendicular ridge of bone, just as blue-black as the rest of his body, and two similar but longer ones flanked his spine. On his chest what looked like a tangle of vines just below his skin, its many ends stretching towards the rest of his body and growing thinner and deeper as they did. A wild tuft of blue fur, more akin to smoke in its apparent consistency, had replaced what used to be his mane, and a similar one began at the middle point of his otherwise barren tail.
The creature stood on all fours, his arms now longer and thicker than his hind legs and his back slightly curved as a result. There was no trace left of the crystal used, not on him or on the machine. He stared at the unicorns with his red eyes, his expression impossible to read for them. His breath was regular, if a little heavy, his nostrils slits at the front of his face that flared open and closed in sync with his chest's motions.
The male unicorn pressed his face against the glass as he stared at the result of their experiment, the full weight of the events finally crashing down on him, while to his side his female companion sat frozen on the ground and felt the same. And they both looked at the creature's eyes, as the creature looked back.
"What have we done?"