I was a complete moron for staying at the summit as long as I did, no doubt about that. By the time I started back the sky had turned dark indigo and the distant peaks were silhouettes.

The slope carried me across a crest on the side of a giant mountain. There was a steep drop along both sides, and with every step I took pebbles broke off the trail. You could tell it was a long way down by the sound they made tumbling into the fog, out of sight. I tried not to think about the jagged rock beds waiting for me at the bottom.

Yep, no doubt about it, I was an absolute idiot. On the way up, a bunch of experienced hikers warned me about ‘hanging about’ too long—said dusk would roll around fast.

If only I’d listened…

Over the course of the next thirty minutes, the sky turned from purple to black, and this silvery mist drifted across the landscape, limiting my visibility to thirty metres or so. It started feeling claustrophobic, despite being outside and all, and I kept second-guessing whether I’d actually come that way.

That’s not even mentioning the jerky winds and the weight of my pack, which by now felt much heavier than 15 lbs.

My phone couldn’t get a signal but worked okay as a flashlight. I waved it in low arcs while doing some quick sums in my head.

The climb took three hours, accounting for water breaks, and I’d only started down forty-five minutes earlier. Yeah, no matter what way you sliced it, there was a long way to go.

The ridge swung left, then right, then left again. At some points it became so wide four people could march along side-by-side, at other times I almost had to do an impression of a tightrope walker.

Thanks to the gusts of wet air, I didn’t hear the footsteps until they were close by. By that stage my light barely dented the fog, which looked thicker than gruel.

I stopped, listened closely. Just a gust of wet air. I started along again.

Ten seconds later a huge pebble cascaded noisily into a ditch up ahead. Did another moron hang around too long? Maybe they had a phone that wasn’t a complete piece of shit and could actually get signal.

“Hello?” I shouted. No reply. Only more air.

I broke into a jog. If I could catch up with another hiker—one who felt more confident about the route—my electrified nerves could take a rest, at least.

A blob took shape in the mist. I repeatedly shouted ‘hello’ as it morphed into the outline of a figure, roughly my height.

I yelled for their attention, arms waving overheard. They waved back.

Already feeling the hardness in my stomach melt away, I eased into a trot and said, “You have no idea how happy I am there’s somebody else up here. For a minute I thought I’d gone the wrong way.”

From that distance, I could tell they were facing me. I said, “Is this the fastest route back to—”

As the figure became clearer against that icy sheet, both it and I froze, our arms suspended in mid-air. Slowly, I let my left hand drop against my side. The shadow did the same. I stepped forward, then back, then off to the side. It did as well.

I was staring at my own silhouette.

Okay, there had to be a scientific explanation for this. Didn’t I read about broken spectres once? Yeah, they’re the shadow of an observer cast in mid-air upon any type of cloud opposite a strong light source. Makes sense.

I took a single step forward. So did the shade. That was fine, you’d expect that to happen. Trick of the light and all…

I took another, slower step. Then another. And another.

Up ahead, the figure emerged from the fog. Now, I could make out navy hiking trousers, a red woolly hat, a fluorescent jacket, and a black backpack.

The same outfit as me.

After another cautious step I saw strands of dark hair poking out beneath the hat, along with a set of green eyes, and the thin, dented nose that had greeted me in the bathroom mirror every morning since my tenth birthday, when I busted my face trying to do a wheelie on my new bike.

The figure wasn’t my silhouette—it was a carbon copy.

I lifted my right leg. Other me did the same. My left hand whipped from side-to-side, twisted at the wrist, testing whether that thing imitated these movements.

It did.

I swallowed a gulp. “Hello?”

The duplicate's mouth moved, although no words came out. For a while, we stood there frozen in place, a showdown.

As I punched the number for mountain rescue into my phone, my counterpart tapped the air with its forefinger. I still couldn’t get a signal.

Okay, so this wasn’t a trick of the light. Did that mean I’d lost my mind?

I opened the camera app and snapped some pictures. The results were all blurred because my stupid hands wouldn’t quit shaking. My brain swung back and forth on whether there was actually a person in those photos.

I decided that even if the thing was real—which it wasn’t—the trail ahead looked too risky anyway. If I kept going, I’d slip and fall, then, in the morning, one of those early bird hikers would find me impaled on a rock. Or maybe they'd spot other me first, and summon mountain rescue to cart the body off in a helicopter, maybe even arrange a little funeral…

I shook these thoughts away. There was zero chance I’d arrived by that path. I needed to double back and find the right one.

I backstepped until the fog swallowed my counterpart, spun around, and followed the ridge up and up, leg muscles burning.

The temperature continued to drop. Soon the air felt like acid in my lungs, and my ears began burning. I’d wasted too much time already. I needed to get off the mountain and someplace warm.

After a fifteen-minute jog, my pack bouncing up and down on my shoulders, the ridge connected with a Y-shaped slope. This time, I took the other route.

The new trail felt more familiar. Steadier. I broke into a run, confident I’d be back at the hostel sipping hot chocolate in no time.

But soon the edges of the walkway tapered off. I slowed my pace, mindful not to slip, and as I did there came a shuffle of steps up ahead.

And then, like before, a silhouette filled the blank sheet of fog.

Okay, this had to be my imagination. There was no other plausible explanation. My arms shot up and down, confirming the doppelganger still mimed these actions. It did. I couldn’t decide whether that was a good or bad thing.

The silhouette stood there, mouth all tight, eyes narrow. What the hell did I do now?

I weighed my options for a while before giving the phone a few more tries, even held it way up overhead. Still nothing. I was cut off. Isolated. Alone.

I’ll go slow, I kept telling myself. If I turned sideways, me and other me could slip right by one another, right? What other option was there? Wait until frostbite set in?

I shuffled along, my pulse banging between my ears. One slow, unsteady step followed another. But then, when only twenty metres of trail separated us, I froze.

What the hell was I thinking? I’d seen this horror movie a million times before. Better to stay perched at the summit until dawn rather than let this scene play out, even if it meant risking hypothermia.

My clone stood there with its face tensed. I doubled back, frequently glancing over my shoulder until the figure melted into the gloom, and then jogged back toward the summit.

The temperature plunged even further. Now icy fingers caressed the back of my neck, massaged my earlobes.

To my horror, the silhouette appeared up the stony hill five minutes later. Despite already knowing what was about to happen, I continued on until the clone drifted into view.

I spun around, sprinted back. I’d let the fear and panic disorient me, that’s all.

It wasn’t long before the footsteps started up again. Another ten strides and the silhouette re-emerged.

Still in denial, I went back and forth six times. With every turn, my counterpart appeared sooner and sooner. Now I couldn’t go five minutes without hearing pebbles crunch under heavy boots.

This had to be a nightmare.

I pounded my temples, clomped my feet, and told myself to wake up, wake up, wake up. My counterpart mimicked these actions.

The wind bit into my extremities. Now simply holding the phone took a concentrated effort. My swollen red fingers looked fatter than plump sausages.

My only option was passing the replica. But hey, it was only a phantom, right? A figment of my imagination. Maybe in the future I’d visit a doctor, explain what happened, and they’d reveal I had a brain tumour…

I drew chilled air into my lungs and then shuffled along, inch by terrible inch. Soon there were only twenty metres between us. Fifteen. Ten.

I slowed way down. Then, as the two of us closed in one another, I pivoted inward, facing the left side of the drop-off. My mirror image swung right, our heels hovering over the edge of the pits. At that distance, we’d still have been able to reach out and shake hands. Not ideal.

I took a single sideward step. Then another. And another. And, as we drifted closer, the corners of my companion’s mouth turned up.

After two more steps I could make out the beginnings of a smirk. My feet remained locked in place as my top half leaned forward.

For every inch that closed between me and it, that mouth grew wider, spreading into a full-on ear-to-ear grin. An invisible ice pick stabbed my insides.

I sidestepped in reverse, my peer's face reverting to a look of terror, followed by confusion. Once we reached a safe distance I tried making a fist but couldn’t. Pressing forward was my only option.

After failing to get my breathing under control, I sidestepped along, quicker this time, my arms up in a t-pose.

As the distance shrunk, my counterpart’s lips curled back revealing a smile so wide and deep you could count the individual teeth. Except, they didn’t look like my teeth—more like yellow canines surrounded by black gums.

The figure's eyes widened and flicked about, as though it had been looking forward to this moment for years. Come a little closer, the expression said, I promise I’m not gonna hurt you…

I couldn’t retreat again. Not unless I wanted the authorities to tell my family they discovered two identical icicles. In an attempt to create more space, I edged so far back that only my toes remained on solid ground. That grinning bastard did the same.

My entire body tensed up, hard. I hunched forward, my head down and to the side. Just a few more steps…

But now there was something happening to other me. The flesh along its cheeks began bubbling, and dark patches grew across the neck and forehead. The facial muscles jerked and twitched, going crazy with spasms, laughing soundlessly. Pink froth shot out of that opened mouth and sprayed across my cheeks. It’s warm, rancid breath made a moist sickness slide up my throat.

One more step and we’d come face-to-face.

I clenched my jaw and forced myself to press on. And, as our heads aligned, the skin on the face opposite mine tore away, as though gouged by invisible fingernails. Soon there was only exposed cartilage and veins, with patches of bone shining through.

The two of us stared at each other, our breaths perfectly synchronized. For a moment I thought I was about to make it—that I just had to order my legs to take one more step.

But then my twin’s head rattled from side-to-side, swaying too far in either direction as if loose at the neck. Without meaning to I yelped, felt my balance go, and then windmilled both arms around. My counterpart did the same. This action carried both our bodies over opposite sides of the trail.

Beneath my boots, clods of dirt broke apart and tumbled into the void. For a moment I became weightless but, at the very last second, my numb hands shot out and fumbled for the trail

By some miracle, I held on. With barely working fingers I clawed my way back to solid ground, so happy to be alive I almost forgot about the mimic.

It took a few seconds before my brain kicked in and screamed: wriggle sideways. I did this while still hoisting myself back up and then belly crawled along, down summit. When there were a few metres between me and my counterpart, I scrambled to my feet, still breathless, and backstepped away. Other me retreated in the opposite direction until the fog enveloped him, and then I spun on my heels and tore down the trail.

Within minutes the slope widened. I started half-running half-falling, but my legs refused to slow down, even when the path connected with the valley below. Whenever the first signpost for the hostel appeared, I almost cried.

I still don’t know what the hell that thing was. All I know is I haven’t been hiking since...