Pomella bolted awake in Bio's arms so quickly that she almost dropped her, Pomella looking around with wild eyes sleep already forgotten. Selena seemed equally spooked, head snapping to look the way they came as another scream echoed off the walls. "What in the fu -"
"You know I don't think we have time for swearing if my ears are working," Bio cut her off, the sound of clicking quickly approaching them from behind causing the cave to echo eerily. Whatever was coming their way, it was huge. Trying to be gentle in her haste, Bio slung Pomella onto her back, the bird-girl wrapping her arms and legs tight around her, nearly choking her. Bio was too busy running to notice something as trivial as choking, her feet a blur as her legs mutated without her influence.
Selena was right behind her despite her injured ankle, fear drowning the pain in the mad dash to escape - whatever it was - chasing them. As if spurred by the sound of footsteps, the creature had increased its own pace, a near-constant sound of screaming following right behind them. Part of it was Pomella, practically yelling in her ear to hurry up, its catching u-
The feeling of hot breath on the back of her neck made her yell in a mix of terror and fury, her legs acting on her own as the footsteps sounded from just behind them. Selena let out a cry as she stumbled, her ankle twisting under her as a faulty step nearly took her to the ground before Pomella managed to grab her hand and keep her from losing her footing. Bio didn't notice, too focused on running to take a break to think.
She felt more weight on her back, Pomella yelling to Selena to hold on as their hands clasped together. They were a pully system, Bio running at inhuman speeds as Pomella dragged Selena along behind them, the poor girl limping on her one good foot. Bio got her first look at the creature as they took a turn, passing a crystalline portion of the cave. The very sight set her entire body into overdrive, fear driving itself like a spike down into her core.
It was long, with clawed hands that reached toward them on long boney arms as thin as twigs. Its body was long and segmented, covered in chitin like substance marred with many scrapes and cracks, exposed flesh leaking yellow puss. It had too many legs to count, almost as if it were a millipede as the sharp ends dug into the stone, leaving the surface so full of holes people with trypophobia would have a heart attack. Its torso was humanoid in shape, bony ribs jutting out unnaturally. But worst of all was its head, extended on a neck as long as its arms so thin you could count the ridges of its elongated spine, sat the face of a human, upside with its eyes torn out to leave bloody holes and a mouth filled with teeth.
A scream tore its way free of Bio's lungs as her eyes locked on its bloody sockets, and any rational thought she had left whited out in that instant. Reaching back she grabbed Selena by the hand, snatching her to her side in one violent motion as her body responded to her distress. Feet and legs mutating further, long, curled claws dug into the stone beneath and launched them forward, legs covered in exposed muscles that contracted and pulled with every stride.
It felt like she ran for years, the sound of screaming and steamy breath pushing her onwards. The cave twisted in turns as if producing convoluted pathways simply to aid in the... 'thing's chase. It couldn't have been more than five minutes in reality, but fear extended that to an incredible extent. She kept hearing it get closer, the panicked voices of her companions as she carried them away. Then at the turn of the corner, she finally saw a way out, a large doorway filled with beautiful sunlight.
But then, just before they broke into the light the creature got a hold of her leg, claws digging into created muscle and locking it in place. The sudden jolt caused Pomella and Selena to rip from Bio's grasp, flying a few feet through the air through the doorway to safety. The creature's second arm shot forward and dug itself into her shoulder, eliciting a scream from her raw throat.
It turned her to face it, and she found herself staring into the black pools of its bloody sockets. Its mouth agape with row upon row of teeth gleaming with saliva. It screamed, and she found herself screaming again with her body using the last of its strength. Without conscious thought her ribs suddenly exploded from her chest, blood spraying out of the sudden self-inflicted wounds as her ribs straightened and embedded themselves into the creature's throat and face.
It screeched so loud it nearly burst her eardrums before it slowly began to melt. The wounds leaking acidic blood as it deflated in on itself as if filled with gas. Bio, having used all of her energy, fell onto the floor, her mind dizzy from blood loss and exhaustion. Her ribs slowly went back to their original shape and position, leaving bloody holes traveling through her body.
The last things she heard were shouts of panic as Pomella and Selena rushed to her side, one bruised and one limping. As her vision darkened, she caught a glimpse of their faces as they looked down at her in panic, and she faintly heard Selena yell "Don't go on me!"
"I'm sorry Selena... At least I c..could protect y..."
Then, on that day, Biovera, the personification of mutation, died.