The four of us sit with our backs against the wall of the cave, watching as the worm's body continues to inch through the tunnel. Something wet drips from my hairline, across my temple and then down my chin. I'm not sure if it's sweat or blood.

I'm not sure if it matters.

"That thing's got to be a mile long or something," America says. He lets out a cough that shakes his entire body.

"No, it's just moving at about the speed of a glacier." Star shifts where she is sitting and groans. "I think more of my body is bruised than isn't right now. I feel like I've been hit by a train."

Despite the grim situation, I can't help but be reminded of sitting in the car and waiting for a train to pass when I was a kid. Lucy always told me that you needed to pick your feet up when you went over the train tracks. It was one of her superstitions—that and holding your breath while you pass a graveyard. I was never sure why she insisted on it, but even as I grew up, I continued to do both. I'm not a superstitious person, but I'm prone to habits, and it didn't feel right not to.

This creature really does remind me of a train. It's so long, and I can't see the end of it in either direction. We're stuck sitting here waiting for it to pass with no idea of how long it will be.

"I think I'd rather face a train over that thing," I finally say.

Star laughs, but her voice is pained. "We weren't joking, were we, Shawn?" she says. "These tunnels really are worm holes. They've all been carved out by those monsters, haven't they?"

"It seems like it," Elias says, rising to his feet.

"Where are you going?" America asks. He pushes himself to his feet as well and heads after him.

Elias walks down the tunnel, toward the wriggling body of the worm. "I'm interested," he says.

"No, you're crazy," Star mutters under her breath, only loud enough for me to hear.

I let out a laugh, followed by a hiccup that shakes my entire body.

"Elias, just leave it." America places his hand on Elias' shoulder. "Just let it pass. We don't need to provoke that thing again."

"I don't think we provoked it," Elias says. "I don't think it even knew we were here."

"It attacked us with its tentacles!" America throws his hand in the direction of the creature. "Of course it knew we were here!"

"Or, we just unfortunately got caught in its path as it stretched." Elias takes another step forward, shaking his arm gently until America lets go. He approaches the monster, pausing when he is a few yards from it.

Star and I exchange glances as Elias examines the creature. America turns to the two of us, rolling his eyes and shaking his head.

Finally, Elias turns back to the rest of us. "Did any of you notice something different about it?"

We're all silent for a second.

"Different?" Star finally says. "The thing is fucking huge. How about that? That different enough for you?"

"True," Elias says. "But think about its mouth. Did you notice anything about its teeth?"

I pinch my eyes shut for a second, thinking back to when its face first emerged from the wormhole. I was so terrified, I was hardly paying attention to what I was seeing. I remember its teeth and its throat—like a deep massive black hole. Nothing else.

Nothing else.

"The worms," I gasp. "The ones that were in Devin after he was bitten. There were no worms in its teeth. The ones that attacked us had little maggots crawling across every inch of their mouths."

"Exactly," Elias points to me, a smile slowly forming on his face.

"So, what does that mean?" Star asks. "Why would this one be different?"

"I think, the worms but must be an infection, not something inherent to the creature," Elias says. "This worm—it wasn't interested in us. We were quiet and still as it passed, sure, but if it was hunting and looking for a meal, I'm certain it would have found us when it entered this branch of the tunnel. Maybe naturally, it doesn't eat meat. Think about it—have any of you seen any animals around here other than us that would be a good source able to sustain a creature so large?"

I chew on the inside of my cheeks. He's right. There were no animals on the surface, not even plant life. The planet is like a desert.

"Then what does it eat?" Star asks. "Without any other life around here, how does it sustain itself? That is, when it isn't infected and feeding on astronauts."

"But there is other life around here," Elias says.

Suddenly, it clicks. "It's like a whale," I say.

Star squints at me and raises an eyebrow. "A whale?"

"It's enormous, but it eats the smallest creatures imaginable," I say. "It filter-feeds off the mold."

"Think of it like an earthworm," Elias says. "I think, it carves out tunnels like this as it eats, filtering the mold out of the dirt and stone. I wouldn't be surprised if this whole planet is covered in a network of these tunnels, dug by thousands and thousands of these worms."

"That . . . disgusting," America says.

"I would have gone with amazing," Elias replies, "but I suppose disgusting is fitting too."

"But wait," Star says, drumming her fingers on her knees. "When it is infected, it eats meat, right? But there isn't any meat around here other than . . ."

"Other worms," I finish her sentence when she trails off. An uneasy, sick feeling turns over in my gut like I've eaten something spoiled. "It cannibalizes them."

"Or, it hibernates," Elias suggests. "I don't think those worms that came out of the starship and attacked us were hatching. I think they were waking up."

I narrow my eyes as I think through what he's saying, trying to make sense of it.

"It's just a theory," he continues, "but I think that webbing we saw around them was some sort of chrysalis they formed to suspend the life of the host—like a deep hibernation."

"But why?" I ask. "Why do you think they were hibernating and not just hatching?"

"Think about it," Elias says. "Those monsters 'hatched' not even a few hours after we landed. What are the chances that we would land right at the time they were getting ready to hatch?"

He pauses for a second. I shut my eyes, thinking about what he is saying. It's a good point. The chance that we just so happened to land right when they were about to hatch is unlikely.

"And why would they hatch in that other starship, of all places?" Elias continues.

I open my eyes and look back at him. His eyes shine in the beam of my headlamp as they meet mine.

"At first, I thought maybe they needed to form a chrysalis to complete some sort of transformation once they were infected," Elias talks at a mile a minute as he gets going, "but then when we saw this benign one, it had all of the same features. Wings, tentacles. Only its teeth were different. They were smooth and blunt, like molars. Good for chewing dirt, not ripping flesh like the teeth of those infected worms. But, when Devin . . . changed . . . his new teeth grew immediately. He didn't need to form a chrysalis first."

"So, the parasites form a hibernation pod for their host when food sources are scarce." Star says. "Is that what you are saying?"

Elias nods.

"And we woke them up when our starship landed," America says.

"Whatever came here in that other starship was its last food source." My voice comes out as a low whisper. "It finished off its meal, and then it bundled up to wait for its next meal." I swallow a lump in my throat. "Us."

"But how long could it possibly stay in hibernation?" Star asks. "That other ship looked like it could have been here for years and years."

"Perhaps, a very, very long time," Elias says. "This was another thought I had—what if these parasites didn't come from this planet? The infection is extremely aggressive once it takes route. Given enough time, it seems like the parasites would take over the entire planet and destroy it. But clearly, they haven't done that yet."

America shakes his head. "You think it came from another planet? But how?"

"The same way we did," I say. "It hibernated for the entire journey."

"Shut up," America chuckles. "Seriously. That's crazy."

"Massive worms with tentacles and wings are also crazy, but you weren't laughing when those things attacked us, were you?" Star narrows her eyes at him.

"Okay, fine, you think it came on a starship or something, then?" America asks.

"Possibly," Elias says. "As a hitchhiker. Or, maybe it came on an asteroid—a part of another planet that broke off, flying through deep space for years and years, carrying this infection with it until it finally landed here."

I bite down on the inside of my cheek. America is right. It does sound crazy—but since we've landed on this alien planet, we've already discovered an abandoned starship, seen creatures I couldn't even have imagined existed, and watched one of our crew mates transform into a zombie.

A chill runs down my spine. Who am I to know what is and isn't possible in the universe? Maybe, a creature could exist that can travel from planet to planet in a state of cryogenic hibernation on an asteroid, protected by its own self-formed pod.

"That's . . . spooky," Star finally says.

Suddenly, the ground rumbles around us. I grip the floor and brace myself as dust cascades down from above. Ahead of us, the worm's body shakes and quivers. Then, it stops moving.

Everything is still.

We're all quiet for a second, exchanging looks as we hold our breath. A bead of sweat drips from my temple and slithers down my neck.

"You've got to be fucking kidding me," Star finally says. "It's just going to stop there like that?"

"I guess it has to take a break from eating eventually," I mutter under my breath.

"It couldn't have cleared the passageway first at least?" Star asks. "Let us by?"

"I don't think it cares," Elias says.

She glared at him. "I know it doesn't care. I was just being dramatic."

"What are we supposed to do now?" I ask. "We can't just go back the way we came. This was the only tunnel. There were no other ways we could have gone. There isn't any other way around it."

"I guess we just have to wait," America finally says. "It can't sit here forever. Eventually, it will start moving again."

With a huff, Star turns and lies down on her back. She clicks her light off and closes her eyes.

"What are you doing?" America asks.

"Taking a nap," she says. "Might as well, right?"

"Shouldn't we keep watch, though?" I ask, but even as I say it, I have to fight back a yawn. Just thinking about lying down is enticing. I hadn't even realized how tired I was getting until Star suggested it.

"Resting isn't a bad idea," Elias says. "We don't know how long it will take for this thing to start moving again. We could be here a while. The three of you get some sleep. I'll take the first shift watching the worm."

"Are you sure," America asks. "I can watch if you want—"

Elias shakes his head, brushing him off. "I'm not that tired right now. I don't mind. You get some rest."

America nods. "Okay, but wake me up in a bit, once you get tired. I'll take the next shift." Hesitantly, he clicks his headlamp off and lies down next to Star.

I know I should get some rest too, so I lie down next to him. I stare up at the ceiling of the tunnel. The beam of my headlamp illuminates the rough texture above with stark shadows. Who knows what could be hiding in them?

But how long will that be? A few minutes? Hours? Days?

We don't have any food or water. We can't stay down here indefinitely. But, unfortunately, it seems like we don't have a choice at this point. Swallowing down my fear, I click my light off and let my eyes slide shut. Even with as tired as I am, I don't know how I'll be able to get any sleep here, trapped in the bowels of this alien world.