Image: Koren Shadmi

The Fog

Elvia Wilk’s surreal, sensuous tale of biobots and their keepers gets to the heart (and nose) of the matter.

Recent advances in synthetic biology, soft robotics, AI, and genetic engineering make it clear that the line between technology and biology is becoming more and more difficult to trace. If an AI can be sentient and a slime mold can solve computational challenges, then what does it mean, exactly, to be alive? Elvia Wilk’s surreal, sensuous tale of biobots and their keepers gets to the heart (and nose) of the matter. — The Eds



The first thing I noticed was the smell. It was not one particular smell, but a barrage of smells, each carrying its own associations. For a moment, I thought I picked up a scent I recognized, but then it was quickly replaced by another in the air before my mind could decide what the last one meant. That crosscurrent drew me across the threshold and into the exhibition room, at which point my eyes tracked upward to take in the moths overhead.

Their glorious wings were different shades of an intense, saturated green. Like sunlight filtering through leaves. Their antennae swooped downward from their bodies in feathered arcs, curling delicately at the tips. Their undersides looked soft, an alien texture I had the strong desire to try to graze with my fingertips. I kept my hands by my sides and sidled along the wall of the room, trying to take all ten of them in.

I’d had a few days of training in a different building before I saw the moths in person, so technically speaking, I knew what to expect. I knew about their strange smells and massive wingspan – nearly as wide as my own with arms outstretched. But who ever really knows what to expect?

I trailed one moth around the room, noticing that its wings were lightly textured with a webbed pattern that reminded me of algae. It spun in circles, then tensed, flexed, and darted toward an imaginary target, like it was testing the air, or rehearsing for something. I caught a whiff of earth or mud, then was suddenly distracted by what seemed like the smell of cardamom –


My supervisor clapped her hands to get my attention. She waved from the entrance. I hadn’t realized she was still there. I gave her a thumbs up, and she nodded and left. It was seven in the morning. I had one hour to get acquainted before my first shift at the Archive began.


Many days passed – weeks, really – until I felt like I had a command of the room, until I knew my place in it. At first I was shy around the moths, uncertain how to approach and touch them; they seemed so delicate and foreign. I thought of something a friend of mine, a physical therapist, had told me: that the most important part of treatment is the first moment you lay your hands on a patient. That first touch has to convey both gentleness and authority.

Once I got the hang of grasping and manipulating their parts and began to feel confident repairing them throughout the day, I went through a period of frustration. The moths were finicky, prone to malfunctioning, always demanding my attention. I wasn’t used to being needed like that. Nobody else depended on me. All the other bots in my life were perfectly self-sufficient. On my way to work in the morning I’d pass hundreds of them busying themselves –surveillance sparrows watching me, nano-bots taking my temperature, swiffers dusting my shoes – and hardly notice them at all. If one broke, another bot would come fetch or repair it.

I thought of the giant green moths as the primordial ancestors of those autonomous bots in the wild, which were made to blend into the background. Watching the moths circle ostentatiously in their room, I found it hard to believe they had once roamed free as well. Now they were here, contained, archived, protected from the outside world. And we from them.


It didn’t take long for me to start thinking of them as my moths, although they belonged to the Archive. I was just their custodian. Still, I was in charge of them during visiting hours. I tended to them by myself while the exhibit was open, from eight to five. I knew them best. And the more I got to know them, the more I liked them. The more I liked being needed by them.

The wall label described them as first-generation dirigible biobots invented for epidemiological purposes. They were, it said, grown from an assortment of cells originating in a species of silkworm moth, who could smell the pheromones of a mate nearly 11,000 meters away.

They did resemble insects, but as if refracted through a strange prism — they were headless, limbless, and their antennae curved downward from the body rather than upward. They were engineered to sense the world in one specific way.

The wall label also explained that my moths had been designed to run on an evolutionary algorithm. That meant that they had been given the capacity to learn as they moved through the world. Their original job had been to fly above cities and smell people, and to learn more about the way people smelled as they moved. I read that they could pick up a hint of illness up to 3,000 meters from a source, not as far a distance as their progenitors, but far enough. When they found a sick person, they sent a GPS coordinate to a server somewhere. They had been the darlings of aspiring biotech engineers and the health ministry, who had been trying for decades to invent a bot that could identify points of contagion in cities. I read that word in a news report: darling.



Until I started working at the Archive, I’d never really seen inside a bot. The new brands were opaque, their workings a mystery. Back in the days of the biobots, a lot of people knew how they worked, how they changed over time. But now you aren’t supposed to tinker with bots, and they aren’t supposed to change beyond downloading a software update. Too many accidents.

My moths’ soft underbellies were kept in place by a bioplastic film that could be easily opened so that someone – me – could inspect their insides and make necessary adjustments. My job was to keep an eye on them and make sure they were running smoothly throughout the day, and when one wasn’t, to carefully capture it and inspect its innards: a jumble of warm, pulsing organic material and cold electrical wires. At night I took them down, one by one, and put them to sleep.

The tips of the antennae contained stem cells from the soft palates of a now-extinct species of Asian elephant. Those elephants were the only other animal able to pick up scents at such great distances. I liked to carefully run my fingers over the antennae and breathe in each of the moths’ unique scents, imagining other creatures, other continents.

There were dozens of exhibitions at the Archive, but mine was one of the most popular. It was always full. Especially with kids. Kids loved the moths. They reached their little hands into the air to try to tickle a belly or grasp an antenna. Tossed gum or pencils at a low-hanging target; crouched and leapt and giggled. I was constantly surveying the 30-meter breadth of the white-walled room to make sure no heads or hands were bobbing above my own height.


I was surprised by the children’s fascination, given how familiar the new generation is with bots of all kinds. But these old biobot models mesmerized them. Perhaps it was their unusual animality, their grace. Or perhaps it was that their behavior had a transparency to it, a curiosity. They too were exploring, childlike.

I quickly got to know my moths’ individual personalities. The vivid lime-green one with dappled wings who loved to soar high, skimming the ceiling. The smallest one, pale chartreuse, always spinning in circles. The one with brown spots on the undersides of its wings that appeared disconcertingly like eyes. Some were more social, predisposed to move together and travel in flocks; others were independent, preferring to dart or dance alone. But they were all clearly part of a group body. How quickly their seemingly random movements could switch to synced-up military precision. One moment natural, casual, improvisational — then suddenly locked into an ancient choreography.

The only exhibition more popular than mine was the tiger den. A holographic animation of an extinct species of cat stalked the edges of the dark space, roaring convincingly and leaping at people who stumbled over their feet trying to dodge its imaginary claws. I never understood the allure of the tiger room. The tiger was long gone. My moths were still very much alive.


At the Archive, I operated on moth time. Slower than human time in some ways, faster in others. Sometimes I thought of myself in machine terms. When my stomach and brain signaled to each other that it was lunchtime, I imagined an electrical current crystalizing into the command line sustenance, and took myself for a refill.


Some days I ate at the canteen with a friend who worked at the security desk. I joked with him that spending so much time at the Archive was causing me to revert to my lizard brain, act on instinct, become a simpler machine. Obviously, he said, with a grin. Zookeepers always start to act like their animals. Dog owners always start to look like their pets.

This was my first custodial gig, but I knew I was good at this kind of work. First requisite experience: some years on a server farm, braiding wires together and resetting electrical panels. Second requisite experience: a year on an agriculture lot. Washing down the pens and spreading feed. What I remember most from my time on the lot were the smells, repulsive when I started and pleasant by the time I left.

I needed a job to live. My moths did not. They only had to exist. They didn’t have to fill in the gaps of daily life—clean up messes, cuddle lonely people—like normal bots did. They didn’t even have to perform the function that they were invented for, to detect smells in the air; their primary sensory apparatus had been disabled long ago. If they were worth money – and my supervisor had emphasized that they were – it was for their historic value as a bygone species, and their beauty.

This is another reason I enjoyed their company. They lived for themselves alone. They made me feel that to be an organism is enough. To be a body surrounded by other bodies – more than enough.



When I was hired, my supervisor told me sternly to resist anthropomorphizing the moths, that is, imagining that they had feelings. But I will say that they seemed the most dynamic in a room full of people. They couldn’t smell people anymore, but I was sure they liked having people around. When the space was packed, I saw a clear correspondence between the movements of biobots and humans. I marveled at that mysterious morphing and congealing and scattering of beings, the patterns that emerge from an interspecies crowd. But maybe my supervisor was right, maybe I was just seeing what I wanted to see.  

At certain times of day, when the space was full and everyone was shifting and bobbing in rhythm, I sank into a peculiar state of mind. I came to think of that feeling as the Fog. It was like being shrouded in a mist that clouded all the senses; I’d have the distinct experience of shrinking, and then of becoming part of something I’d thought I was external to. It was a feeling of being mixed up, then dissolved. I forgot myself.

But then a moth would glitch or stammer or start to drop in altitude, and I’d have to run out, dodging elbows and shoulders and catch it, with my hands or a long net I always kept within reach, and bring it to the little alcove at the back of the room and handle it. I would flip the moth over to release the catch of its undercarriage — tricky if the wings were still flapping, but as soon as it was open, it would immediately stop in motion, briefly arrested so I could perform my work.


Those were intimate moments. First, I always checked to make sure the electrodes made proper contact with the spongy cells nestled within their organic-artificial exoskeletons. Next, I prodded gently at the soft helium pouch nestled at their center that made sure they could stay afloat should their wings completely fail them. If I felt the slightest laxity in the membrane, I refilled the pouch from a little helium tank.

The moth with spots like eyes on its wings had the most problems. Something was always going on with its antennae; dust got lodged in the feathers or they drooped too far down. It struggled to maintain buoyancy. I learned to keep it in my line of sight, and eventually I started to feel like it was staring back at me with those big brown irises. We regarded each other often.

The moth with eyes happened to have the most enticing scent of all. It was a warm smell, maybe something like a log fire, with a hint of spice, like cloves. I sought signs of emotion in this one especially, despite knowing rationally that it was not an animal, that it computed and sensed but did not strictly think or feel. There wasn’t even a real uncanny valley in effect – it didn’t look like a kitten or speak my language. But still. People see faces in clouds and hear words in transmission static. People find people in everything.


In my neutral clothes, I receded into the Fog most of the time, but sometimes visitors asked me questions. The most common question was the obvious one: why had these creatures been retired? They were so lovely, and they must have been so useful! Didn’t we need them now more than ever?


“Just sniff,” I’d explain in response. “Smell that?”

Nobody knows how or why it happened, why the moths began to emit their own powerful and otherworldly smells. They were built in order to sense us, but somewhere along the line they evolved to manufacture their own smells, too. This was a truly unexpected emergence, a cellular miracle. In my mind it was a feature, not a bug, but the scientists of the time saw it differently. The health ministry quickly took them out of commission. My moths had been the first generation of their kind, and they were also the last. Bots today do as they’re told. 

“But I like that smell,” one teenager insisted, frowning. “Or I don’t mind it, I guess.” I nodded. I understood his ambivalence. That was the problem.

“A lot of people didn’t like the smells,” I told him. In fact, some people couldn’t stand them. Some people went crazy.

The scent of one moth did make me anxious. It was a mottled, grayish green and its smell had a metallic tang that left a bloody taste at the back of my mouth. I never felt the urge to attack or to harm it, but my visceral reaction helped me understand why people might have been driven to extremes. And of course there’s the fact that people don’t like being watched by creatures they can sense — they like their surveillance invisible, forgettable.

More than once I brought that anxiety-provoking moth down for repair to try to find out where its infuriating odor was emanating from, but of course I had no more luck than any of the disappointed researchers who couldn’t identify the specific region that had emerged of its own accord. That is: the part of the moth that wanted its purpose to extend beyond recognizing and analyzing us, the part that desired us to recognize it too.


By my third or fourth month on the job, I was sure my sense of smell had heightened. After a busy hour I might catch a whiff of sweat drying on my chest, and only then register my exhaustion. Or I might sniff a hint of perfume or hairspray and quickly pinpoint the person who had imported the chemicals. I smelled with a new articulateness. I smelled faster.


Kids can sense vulnerability. They bear down on a weak link.

One morning I caught a little girl yanking down the moth with eyes by its weaker antenna. She was maybe seven or nine, and short – I don’t know how she reached it. She must have been there on a school trip, since there were no parents around, just a swarm of other kids egging her on. The moth lifted and drooped as she pulled it all the way down. It looked to be gasping.

I walked briskly toward the scene and wrapped one hand firmly around the girl’s arm, startled by the strength of her grip. She was hugging the moth by then, her arms around its body and her face against a fluttering wing, as if she were clinging to a parent’s leg.

I grasped one wing with my other hand and noticed that its surface felt more familiar to my touch than the girl’s soft flesh. She refused to let go — instead she turned her lips to the moth and nuzzled its belly with startling tenderness.

I pried her away as carefully as possible and scanned the room. That’s when I saw him, a man with graying hair and a blue backpack, watching me like a hawk. I recognized a certain sour smell about him and pegged him as a repeat visitor. He shook his head slowly at me, but I realized his eyes were fixated on the moth in my arms, not on me. He was glowering at it with something like bitterness, or fear.


He approached me slowly and I realized that his pungent sourness was the smell of infection. I thought he was going to say something about what the little girl had done, or what I had done to her. But instead he asked me, eyes cast down at the moth in my arms, whether these things could still identify people. “That one’s been following me,” he whispered, pointing toward me, toward the moth with eyes.

I assured him that the biobots were no longer active. “They don’t track people anymore,” I explained, “and they don’t send GPS coordinates. The part of them that could make decisions has been disabled.” I repeated, firmly, that he had no reason to worry. What I didn’t tell him was that my own sense of smell was active enough to know why he was nervous. 

I didn’t mention the incident to anyone and hoped no one would check the security cameras. I tended to the damaged antenna myself. As I repaired it, I regretted that my moth was no longer evolving, no longer learning how to exist in the world or sense human behavior. It really did need me.


Smell does things to you. It bypasses the logic centers, yanks up deep memories. As I walked around the Archive room, one moment I’d be a teenager kissing in a pine forest; another moment I’d be on a dock, hands covered in the foul but enticing smear of fish guts. Another moment I wouldn’t know where I was, but my heart would clench in feverish joy.


The moths rubbed off on my hands and clothes. Each evening I came home smelling like my whole life. Smelling like whole centuries. I came home having time traveled. Although I couldn’t be sure that other people picked up on it, I became self-conscious about the way I smelled. I worried about bothering people, and also, I admit, some part of me wanted to keep the smells to myself. I started to avoid crowds. I saw my friends less. When my family came for a visit I planned our dinners outside, hoping the wind would scatter the molecules clinging to my body.

The moths acted no differently during our days together, but my time with them became more thrilling as I became more attuned to them. I could easily identify each one by smell. There was the floral tint of the small, pale moth, the grassy freshness of the ostentatious bright green one. I could sometimes sense a disturbance in the swarm before it happened.

One day a talcum-scented woman in her seventies approached me, and excitedly announced that she had seen these bots before. I figured she meant she’d been to the Archive, but no, she cut me off – “When I was a kid,” she said. “I couldn’t forget them,” she said, “the way they bob around! And that sweet smell….”

Another day a man whose clothes were washed with supposedly unscented detergent asked me why the bots needed a human custodian. “Can’t other bots take care of them?”

In a way, he was right. New bots could do the mechanical work; new bots could speak to visitors; new bots could sense smell. In my interview, my supervisor had simply told me that I was needed in order for the exhibition to be “authentic.” Because that’s how life was, back when the talcum woman was young: people and biobots, all part of the same world, in reciprocal communication. I was as much a part of the display as the moths were.



In my kitchen, after work, I started to experiment. I cooked. I made extravagant dishes laced with thin threads of brilliant red saffron, tiny cumin seeds, fresh marjoram leaves, budding thyme flowers still attached to the stem. White peppercorns, tingly Szechuan peppercorns, bright emerald peppercorns, spicy pink peppercorns. A kind of cardamom-laced ginger called Grains of Paradise that I found in the back of a shop. I followed recipes for a time, but then I started to follow my nose. I grazed the aisles of stores far from my neighborhood, bent at the waist, taking in the notes and letting inspiration wash over me.

Chemicals bothered me, gave me migraines – the train became unbearable, with the awful Fog of ammoniac perfumes – but the world of plants! Fruit was ecstatic: I filled first the kitchen and eventually the whole flat with bowls and colanders and cups of citrus. Even at the fruit’s first stages of decomposition I loved the tinge of rot, the beginning stages of matter returning to its source materials.

In this way I came to understand how sterile the city was, and how much the moths had given me. I came to view the appliances that lifted my blinds and maintained the temperature in my flat with melancholy, even pity. They did not feel or smell or taste the world, and I couldn’t feel or smell or taste them. They were as silent and innocuous as they had been designed to be, and there was no transit between us.



I blame the rain for my lapse. It was a torrential, monsoon-like day. The crowds were thinner than a typical afternoon, and everyone who made it inside was bedraggled and dripping. Humidity saturated the air, and the smell of warm rain rising off jackets and skin overpowered me. I was standing in the alcove facing away from the entrance, trying to block out the extra information.

Still. I should have caught it. The same blue backpack. The same sour stench of infection. Nauseating! But by the time his scent had spiraled toward me through the Fog and I turned around, it was too late. His head was cocked back and mouth slack; he was staring up at a school of moths flapping in heavenly synchrony, but he was fixated on the one with eyes, which was bobbing lower than it should have. Suddenly: he clawed the air and snatched it — grabbing one antenna and then the other, then heaving the whole body down with him to the ground.

Adrenaline, air whipping toward me. I was on him in a flash, flattening him, my knee on his chest. My heart was thudding in my ears. I felt the warmth of his body, his chest heaving. I was inundated by the smell of danger, his awful contagion surrounding us. Then I saw it: the moth was completely crushed beneath him.

A custodian is a guardian and a janitor. A custodian has responsibility without much authority. Regarding the incident, my supervisor explained that I had overreached, taken charge of a situation I was not equipped to handle. On the other hand, she said with sympathy, I had always taken good care of the biobots, and she knew I had the best intentions when it came to safeguarding the Archive’s precious artifacts. When I protested that the man was certainly a vector of disease, she only shook her head and quietly reminded me that now we have other bots for that. They’d certainly find him if he were really a threat.


A few months later, after finding a new job, I returned to the Archive as a visitor. In the moth room I found a thick pane of plexiglass stretching from floor to ceiling, bisecting the space in two and sealing the creatures off from the people. The moth with eyes was nowhere to be seen. I smelled nothing. I let my eyes follow the familiar, still glorious shapes of the other nine, but I was sure they moved differently now. Occasionally a wing batted the glass, or two moths bumped into each other. They traced the same paths again and again. They were being played on repeat, like the tiger. Perhaps the moths didn’t care, but I did.

Afterward, feeling adrift, I decided to visit the city aquarium. I hadn’t been there since I was very young. Aquariums have always made me slightly nervous. As a kid, I remember feeling unable to trust the glass to keep all those tons of water from bursting out and taking over. I also remember the frustration of separation – I wished I could jump in the water and see the fish from the other side of the glass. An aquarium gives you a window but in doing so reminds you how separate you are.

I looked at the map and found the stingray tank. I peered at the winged animals for a long time. But they were entirely unfamiliar, with their bulbous eyes and smiling mouths, their smooth movements, their easy sociability. After so much time spent with my half-animal moths, these natural animals seemed like aliens.

I happened to pass by a freshwater tank while a custodian bot was feeding the fish inside. They were zebrafish: small, unassuming, striped minnows darting around in perfect concert. The custodian extended a jointed metal arm and dropped a piece of meat into the water. I watched as the fish gathered and bolted toward it en masse. The whole swarm began delicately nibbling at the meat.

I asked the custodian what had attracted the fish to their food. In a woman’s voice, it replied: “Zebrafish are irresistibly attracted to a chemical compound called cadaverine. This compound is repulsive to humans but it smells delicious to the fish.”

“Fish can smell?” I asked.

“Why, yes,” the custodian told me. “Zebrafish have an especially heightened sensory apparatus. They can pick up a trace of their favorite food from hundreds of meters away.”

I don’t mind the loss of my moths so much anymore. I have a new job at a quiet, rather sterile server farm, but even there I find novel, unexpected smells, all the more rewarding for their subtlety. And I spend many mornings and evenings entranced by the small aquarium I now keep between my bed and the window. I press my nose to the glass and watch my bright green fish, imagining what they are learning and what the water smells like to them. I sprinkle the odorous brown pellets of food onto the surface of the water and watch them sift slowly down, as the fish race toward them. I sink into the water alongside the fish. I sink into a Fog that has condensed so fully it is now liquid. 


This story was also published offline in the catalog for Anicka Yi's exhibition In Love with the World at the Tate Modern in 2020.