Chills rush through my entire body, freezing me in place.

"Shawn!" America calls next to me, but it feels like his voice is miles away. I feel his hand grab my arm. "We have to get out of here!"

Elias' screams gargle as the zombie continues to attack him. His light flashes around the alcove like a strobe.

There is nothing I can do for him. Even if I helped him fight the creature off, he's still been bitten. The infection is burrowing its way through his bloodstream. He's a dead man.

My nose burns as I pull a breath of icy, damp air into my lungs, and I run. America pulls me along as he and Star shine their headlamps ahead. The beams cast long shadows over the rocks and stones littering the cavern. I makes sure each step I take lands on flat ground, terrified of tripping or twisting my ankle if I misstep. If I stop for even a second, one of the zombies might pull itself from the ground and attack me.

I can't fall. Not right now.

I grit my teeth against the pain and keep going.

When America and I reach the ledge at the edge of the alcove, we leap the four feet to the base of the main chamber. I land solidly on my good leg, but my toes slip on the wet mold beneath me. Skidding forward, I throw my arms out in front of me and catch myself on my hands and knees. Without missing a beat, I scamper back to my feet. The lights of my only remaining crew mates—the only other humans left on this entire planet—beckon me.

Finally, America and I reach Star.

"They got him!" I gasp, leaning over and bracing myself at the knees as I pant. Sweat slicks my skin, stinging and burning the tiny cuts on my face and neck. "They bit him."

"We know." America says. He glances away for a second, the beam of his headlamp illuminating the dirt at his feet. Finally, he returns his gaze to me, careful not to shine his light directly in my eyes. "We all saw."

"Come on," Star puts her arm around me, trying to push me along. "We've got to keep going. We've got to get out of here."

"How?" I pant. "We're still trapped down here. It's only a matter of time before those monsters get back up, or worse, Elias as what happened to Devin—"

"Wait, over there!" Star interrupts me before I can finish the thought I was terrified to say aloud. Star directs her light at the far end of the cavern, beyond the stagnant lake. "Look." Her headlamp casts dark shadows around a small gap carved out between the jagged stones near the top of the cave wall. It's a tunnel—one that leads up!

"Do you think it might lead out?" America asks in a rasping pant.

There's no way to know for sure, but it's the best option we have—the only option we have.

I nod "It will." It has to. "Let's go."

The growling and croaking of the undead humans grow behind us. Star lets her light flash over to the alcove for only a second, illuminating the forms of two of the creatures as they slowly pull themselves off the ground. Blood drips from their smashed in faces, and their limbs bend at awkward and unnatural angles. One of them uses its left arm to snap the joint in its right arm back into place. The crunch and clunk of bones scraping against bones echoes through the cave.

"Great," Star hisses under her breath.

Without another word, the three of us run. I limp along beside America, trying to keep as much weight as possible off my ankle. Star rushes ahead. She glances at the stagnant pond as she charges around it. Her light reflects off the deep red surface.

It's the closest I've been to the water—the clearest look I've gotten at it. It's not as opaque as I thought it was when we first found the chamber. Now, with light shining directly on it, I can see a few yards into the murky liquid. Beneath the surface, clouds of red swirl like a whirlpool in slow motion. Out of nowhere, a huge, dark mass moves through the water like a ghost, dragging the current along with it.

I gasp, but before I can look any further, Star directs her light ahead, at the side of the cave we somehow have to scale, and the pond goes dark once again.

Cold sweat drips down the back of my neck, and the scent of rot and mold fills my nose. "There's something in the water," I gasp as I try to keep up with America.

"What?" he pants.

"I don't know," I say. "But I saw something moving in there! Something big!"

The sound of splashing echoes up from the pond. Immediately, America flashes his light over to it. Rings of ripples swell out from the center of the dark water, bouncing back when they reach the edges. The entire surface undulates like someone has dropped a stone into it.

"What the fuck was that?" Star turns back to face us.

Before America or I can answer, a crash of rushing water explodes from the pond. A huge mass rises out of the center like an enormous vine shooting up to the ceiling. Red water dripping from shape as it spirals and curls. In horror I realize what it is—a tentacle. It has to be over a yard in diameter—even larger than the one that nearly crushed us when we crossed paths with the worm burrowing through the cave.

"Oh my God!" I scream.

The massive arm smacks down into the pond with a thwack, sending a huge splash like a geyser into the air. I throw a hand up to guard my face against the spray.

As the tentacle disappears the turbulent pond, a deep rumble shakes through the entire cave. The ground vibrates, and rubble and dust cascades from above.

"Oh fuck," I hear America say next to me.

Then, with an explosive rush, the head of the worm shoots out of the center of the water. Its pink body is ridged and segmented like an earthworm, but it's as big around as a semi-truck.

A ring of teeth opens, consuming the creature's entire face. A foam of bubbling saliva and maggots curdles between the sharp incisors, and tiny parasites crawl across every inch of the creature's skin.

It raises two tentacles from the water, extending them out at both side of its slimy body. The appendages whip around, smacking and splashing at the water as the monster emits a horrific throat-smacking click—searching the cavern for its prey—its meal. The pair of wings sprouting from its back rise from the pond next, dripping with water as it stretches them out. They vibrate and shake, sending a misty spray through the air. I snap my eyes shut as the cold water splashes across my face.

"America, Shawn, run!" Star shouts. She breaks into a sprint, heading towards the tunnel at the other side of the cave.

Next to me, America is frozen in place, staring into the gaping mouth of the beast.

"America, let's go!" I grab him by the arm and drag us in a wide arc around the pond.

The creature lowers itself back into the water, croaking and sucking as its body undulates. Like a squid, it thrusts its tentacles to propel itself through the murky water. When it reaches the shore, it slams the heavy appendages on the rocky cave floor. The ground shakes beneath my feet. A surging wave crashes behind the monster, spreading like a stain and soaking into the damp stone at the edge of the pond.

The monster pulls itself out of the water on its gut and barrels towards us. I push myself to keep running, but the creature is too quick. When it gets close, it sweeps a tentacle through the air at us.

"Look out!" I scream.

America and I dive to the ground. A wet, slimy tentacle grazes across the back of my head as I fall. I land flat on my stomach with a thump that pounds through my lungs.

America lands next to me. His light flashes in my eyes for a second. "You okay?" he asks.

"No, but okay as I can be," I respond.

Behind us, the guttural grunting of the worm blasts through the cave.

America glances over his shoulder for a split second. "Look out!" he shouts.

I begin the push myself up to run, but he grabs me by the wrist.

"Stay down!"

I drop back to my stomach just fast enough to avoid the tentacle of the monster as it swings the appendage over us. The gasp of wind that follows sends my hair flying around my face.

"Go, go, go!" America shouts.

I slither along on my belly until I find my bearings enough to pull myself to my feet. I throw my hand back towards America. He takes it, and I pull him up behind me.

"Where did it go?" I gasp as we run. America and Star's lights flicker wildly around the cave. My mind spins with dizziness.

"On your left!" I hear Star scream from the distance.

A beam flashes to our side, lighting up the face of the monster. Water drips from its teeth like drool as parasites churn up from the flesh of its gums. They crawl and wriggle as they ooze over its lips. Some of them get caught in drops of water and splash to the floor, spreading their disease.

We have no weapons, so all we can do is run as the monster closes in on us.

"Over here, you piece of shit!" Star screams. A rock flies through the air, striking the worm in the side of its ugly face.

The creature pauses for a second. It swings its head around as it emits a guttural throat-smack like a beam of sonar.

It's searching.

Star keeps her light on the monster as she slinks along the back wall of the cave. Even though America and I can see her clearly in the beam of his light, to the blind worm relying on echolocation, as long as she keeps quiet and moves slowly, she's camouflaged against the jagged stones.

The monster searches for another few seconds before finally releasing a frustrated caw. It barrels towards the location Star screamed from—the spot where she was less than a moment ago.

When it crashes against the stone, the entire cave shakes. Rocks and small stalagmites rain down on us. My lungs burn to scream, but I don't let myself make a sound. I throw my hands over my head for protection as America and I dash the last few yards and meet Star at the edge of the cave.

"Quiet," she mouthes as we all lean back against the jagged, rocky wall.

I pant as silently as I can, my lungs burning as I catch my breath.

Star motions up with one finger. America nods and we follow behind her as she climbs.

At the base of the cave, the rocks protrude enough from the wall that we can climb it like a set of enormous, steep stairs. I pull myself up with my arms, using my one good leg to kick off from each landing. My fingers burn as I grip at the rough surface of the cave.

The worm continues to writhe and moan with frustration as it smacks its tentacles into the side of the cliff, but it's searching for us in the wrong spot.

By the time we are halfway to the entrance of the tunnel, the cliff face steepens. I claw at the sides and shove my toes into small crevices, but I can't get a strong enough grip. My fingernails strain like they are going to snap off inside of my gloves.

I whip my head back, flipping my sweaty bangs out of my face as I glance up to the tunnel above. It's still another dozen feet or so above us.

Someone taps me on the shoulder, and I nearly scream as I jump, startled. Star's light blinds me for a second before she directs it up.

"Boost," she mouths the word to me and mimes grabbing something and raising it above her head. She glances between America and me. "Then you pull me up."

The creature draws closer with its search, the sucking and smacking sound growing louder. I know we don't have much time.

I nod at Star, and she doesn't waste a second. She and America grab me by the ankles and raise me towards the entrance of the tunnel. I brace myself against the side of the cave for balance. They extend their arms above their heads, and I reach the ledge of the tunnel with the tips of my fingers. Sweat drips from my hairline as I strain to get a solid grip. With all of my strength, I kick off from my friends and pull myself up. After getting my chest flat against the rocky floor of the tunnel, I swing my legs up. Immediately, I turn back to face America and Star.

"Come on," I mouth the words as I lay on my chest and extend my hands to them.

Star crouches as America climbs onto her shoulders. She stands, raising him above her head. His light blinds me, but I don't need to see. I reach out my hands to him. When I feel him grab my arms, I grip his wrists. Using every ounce of strength I have, I pull him the rest of the way up.

As he gains his bearings, I roll on to my back, panting. I push my hands up to my face and shove my hair out of my eyes. Sweat stings the tiny cuts that cover every inch of my exposed skin.

America taps my shoulder, and I find my strength again. We can't stop now.

We lean over the ledge and extend our hands to Star. She jumps—stretching her arms above her. Her gloved fingers connect with mine, but they slip through.

She pants as she glances over her shoulder at the monster. It slams another tentacle against the side of the cave, and a shower of dust cascades from the top of the tunnel, coating America and me in dust. I hold in the cough that burns in my throat.

She backs up, preparing for another leap. Then, she thrusts herself into the air, and her hand clasps around mine. I grip her as tightly as I can, but her momentum causes her body to slam into the rocky side of the cave with a bang.

The beast hunting us freezes in its tracks at the sound, and its head immediately snaps around to face us. It lets out a smacking croak from its throat. Its wings twitch and vibrate behind it, and it swings its tentacle out.

"Shit!" Star screams.

The wet, slimy appendage smacks the side of the cave right beneath her.

"Pull me up!" she screams. Her eyes stare up at me, frantic. "Shawn!"

I stretch my other hand to her and strain as I raise her up towards the tunnel. I feel America's hand wrap around my waist, helping me to pull.

There is another smack, and Star screams again. With a jerk, the weight I'm holding triples, and her hand slips through mine.

"Jess!" I scream.

"Oh my God!" she cries. Her mouth gapes open, a tentacle wrapping around her at the waist. My glove is torn from the arm of my spacesuit as the worm yanks her back.

"Fuck! Help!" Her screams turn to gargled, guttural wails as the monster constricts around her torso. With a bang, it slams her into the rocky floor, and her helmet shatters around her skull. Her headlamp bursts with a flash, and only America's light remains.

A shudder rushes through my entire body as the monster's infested mouth dives in at her. A few final screams come out of the carnage before she goes silent, and the only sound that remains is the squishing and crunching of teeth devouring flesh and bone.