With a loud squelch, Rio came tumbling down to the floor with a resounding thud, the limp body of the student across her, completely dead weight. With a bit of a struggle, still regaining lost energy she had been sapped of before reaching the cavern, she lay the student beside her. Deathly pale, dull hair, grey skin, and milky eyes. Their skin was cold and clammy to the touch, and they appeared to be very, very dead, if it wasn't for the fluttering pulse that she felt in their wrist, she would have completely believed them to be dead. More revolting squelches sounded from the ceiling, tar peeling away and dripping onto the floor. It jiggled and spread out as it smacked the floor, but did not splash, and eventually thuds followed the tar as one by one the students hanging from the ceiling were dumped to the ground.
Her ears flicked, and swiveled in a few circles, trying to pinpoint... something. The noise was nearly silent, a sort of hissing sound. It rolled through the tunnels around her, quiet, flowing as if made of water and steam, gurgling repulsively every few seconds. Her eyes glanced in the dark, the tar like substance was barely visible in the dark. She watched, listening to the hissing get louder over a time that felt like hours. The tar moved.
It twitched, and shook, before scooting a few inches with a sucking sound as it peeled itself off the floor. In the dark, she noticed it shimmer, become more liquid like and seemed to only grow darker. Suddenly, the hissing began to increase, the sounds of fluid moving growing louder as the tar reared up like a large, black wave. Tendrils of the black substance rapidly sank to the cavern floor, creeping through cracks like the stone was bleeding, rolling out of the tunnels as if water was rushing in to drown them. The tar combined itself, twisting and swirling into a massive, irregular pile of tar. The hissing stopped and the tar went limp.
"We need to leave-" Rio gasped after some precious seconds of silence, but it was too late now. The tar reacted to her voice, springing up with a scream. Tendrils of tar shot out from the pile, latching onto the comatose students in the room, dragging them into the mass before anyone could so much as lift a finger to prevent it. The moment they hit the tar their bodies seemed to dissolve, peeling apart as easily and messily as cotton candy. Rio gagged in horror as the pile pulsed and shuddered until every student had been captured.
The pile sprang up into a massively humanoid shape, stick like and clumsy, dripping the tar as if it were extra and unneeded skin. The nearly twelve foot tall figure twitched, the sounds of peeling and growing muscles seemed loud to Rio's ears, as the body filled out with layer upon layer of lean and limber muscle. The figure, with a round stub for a head, stretched out a neck, something snapped and popped within as a skull began growing. The legs, not human and more animal, suddenly cracked as the feet sprouted scythe like claws made from bone, and the legs took on a vaguely skeletal appearance with hastily formed muscle glue to them. A tail sprouted from the base of the spine, splitting with the sound of tearing flesh into three long and arrow tipped whips. The arms bulged as they suddenly had a new spurt in length, the fingers popping as they instead became boney claws. Something crawled beneath the ribs, pushing against the skin, until with a great rip four more arms sprouted from the things sides, spraying the tar everywhere. The tar was still liquid and undeveloped along the monster's back, waving like many tentacles that eventually found purchase against the ceiling. The skull grew more, every boney feature defined as no muscle grew over the face. Barely any skin was pulled over the gleaming grey bone, which stretched into some mix of a long snouted creature. Ragged, matted, thin fur sprouted from the long neck like needles, leaving the rest of the body to be covered in sickly thin skin. Suddenly, the stomach and base of the neck ripped open, causing the neck and back to arch backwards unnaturally. These gaping pits suddenly grew boney spikes along the edges, and an inky tongue ran itself over the newly formed teeth before both new mouths turned upwards into a devilish grin. The skull suddenly split into thirds, the jaw hanging broken and wide. The fangs only grew larger, and the beast's tongue hanging limp. The sockets for its many eyes remain dark and empty, and its forehead suddenly ripped open to reveal the sickly amber eye in its forehead.
Rio listened to the sounds of the monstrous forming of the beast, nearly loosing her lunch, and instead a strangled sob at the mere sight of the thing escaped her. Sensing the shift in mood, the thing opened its mouths and screamed. "RUN!" The headmistress screeched, leaping to the side and scrambling around on all fours as the tendrils from its back launched after her. The beast clumsily swung its newly formed arms and tails around, scarring the stone around it deeply, but luckily seemed to miss everything it aimed for. Rio roughly snatched Sky by the collar of his shirt, dragging him with her into the tunnels. "DON'T FIGHT IT, JUST GET OUT!" she yelled behind her, scrambling around blindly as she didn't dare give off any light in the dark. She heard the tar squelch behind her, and she pushed herself faster, feeling something breeze past her. Her dragon-y screeches were hastily cut off and muffled, her breathing labored as she dragged the extra weight of her currently powerless friend, blindly trying to escape the caves.