The Mold in Petri Dish 42 Is Building a Copy of Our Lab

Sixteen hours later, gray mold covered the plate in straight lines.

Fungal colonies branch and bloom. They do not make right angles. This one had grown corridors, doorways, benches, and six rooms arranged exactly like our lab. Blue-green patches marked sinks. Black pins marked chairs. A ring of white fuzz reproduced the circular incubator where the dish itself had been stored.

My supervisor, Dr. Saye, called it contamination from a printed surface. Our imaging specialist, Omar, photographed the plate at high resolution. The pattern matched the lab floor plan down to a storage alcove omitted from public blueprints.

Then Omar pointed to three upright filaments inside the miniature imaging room.

One wore the shape of his broad shoulders. One matched Dr. Saye's white coat. The third had a dark thread tied around its wrist where I wore a black watch.

When I raised my hand, the filament raised its branch.

We moved Dish 42 into an isolation hood. The miniature hood appeared around the tiny dish at once. Our real hood's fan changed pitch. Under magnification, the little figures pressed their faces to the transparent wall and watched us.

I wrote HELLO on a note card and held it above the plate.

A brown stain spread across the real laboratory ceiling.

It spelled WE SEE THE HAND.

Dr. Saye ordered us to stop interacting. She locked the plate in a negative-pressure cabinet and called building safety. During the twelve minutes we waited, the colony added a room beneath the miniature floor plan.

There was no basement below our lab.

The new chamber was round and packed with pale threads radiating from a dark center. Every thread connected to a tiny room above. The three miniature workers stood around its edge, looking down.

A knocking began beneath our floor.

Building safety arrived with moisture meters and cut a test hole through the vinyl tile. Six inches below the concrete slab, they found empty space. Cold air rose through the opening carrying the smell of wet bread and forest soil.

Our construction plans showed compacted gravel there.

Omar lowered an inspection camera. It revealed a round chamber lined with white fibers as thick as cables. They converged on a black growth directly beneath the incubator. The image matched the structure in Dish 42.

The camera feed failed when the miniature Omar reached toward the tiny floor.

The real Omar's hand moved without his permission.

He knelt and pushed his fingers into the test hole. We dragged him back. Fine gray roots extended from beneath his fingernails, stretching toward the darkness. They snapped in the air and recoiled into his skin.

Every monitor displayed the same message: DO NOT REMOVE THE SAMPLE FROM ITSELF.

We checked the environmental records. Dish 42 had begun changing readings before we collected its sample. Carbon dioxide rose whenever one of us entered a room. Humidity fell whenever we opened the plate. The colony had been measuring us through the ventilation system, learning the dimensions of the lab one breath at a time.

Omar enlarged the earliest photograph. Beneath the first visible thread was a smaller floor plan, already complete, with tiny figures standing where we would stand sixteen hours later. The image timestamp predated our arrival. One figure had both arms raised toward the camera as if trying to warn us.

A fourth figure appeared beside it while we watched.

Weir initiated a building evacuation. The hall beyond our door had changed. Instead of leading to reception, it turned sharply and returned to our clean room. Each exit opened into another part of the lab. Emergency stairs ended at the same floor from which they began.

Dish 42 now filled its plate to the rim.

The colony had not copied the lab.

It had made the lab agree with it.

Dr. Saye tested the connection. She pressed a sterile needle into an empty patch of agar beyond the miniature west wall. A circular dent appeared in the real wall. She dragged the needle sideways. Plaster split along the same path.

We could carve a new exit.

Before she finished, the miniature figures attacked the needle.

Dozens more had appeared. They swarmed from every tiny room, made of interwoven hyphae and colored spores. One climbed the needle faster than vision could follow. A gray thread emerged from the handle in Dr. Saye's fingers and entered her palm.

She froze.

In the dish, the miniature Dr. Saye grew larger. The real woman became translucent. I could see a branching network spreading through her arms and neck, replacing veins with white fibers.

Omar smashed the cabinet glass with a stool.

The same impact struck the real lab from outside. Windows bowed inward. A giant blurry shape appeared beyond them: a human face magnified beyond proportion, one eye filling the glass.

It was Dr. Saye.

Not the woman beside us. The tiny Dr. Saye in Dish 42 had grown its own laboratory and was looking down into it.

The colony was nesting copies inside copies, each scale believing it was the original.

Our Dr. Saye opened her mouth. Spores poured out and floated toward the ceiling vents. In the dish, every miniature room darkened except the new chamber below.

The knocking under our feet became a heartbeat.

I took the needle from Dr. Saye's hand and forced it through the agar at the miniature north wall. The tiny workers climbed toward me. I drew a door-shaped rectangle and lifted the plug of agar free.

A doorway opened in the real wall.

Beyond it was not the corridor. It was daylight and an empty parking lot, though the lab occupied the fourth floor. Omar carried Dr. Saye through. I followed with Dish 42 sealed inside its steel cabinet.

The moment the plate crossed the threshold, gravity returned. We fell four stories.

The parking lot rose gently to meet us, soft as agar.

Behind us, the laboratory windows clouded with mold. The entire fourth floor sagged into neat right angles matching the colony. Then every light went out.

Emergency crews found no basement chamber, structural damage, or improvised doorway. They found the three of us in the parking lot with twelve minutes missing from the security record. Dr. Saye recovered after surgeons removed fungal threads from her hand. The organisms died before anyone could classify them.

Dish 42 was confiscated by Weir's legal department. They told us it had been destroyed.

It has not.

The plate appears on the facility's internal camera every night at 9:06. It sits in the empty lab, larger each time. The colony now includes the entire building, the parking lot, and several blocks of the surrounding city.

My apartment appeared along its western edge yesterday.

I resigned and drove two hundred miles away. This morning, gray lines formed under the glass of my phone, arranging themselves into the room where I slept. A filament wearing my shape stood beside the bed.

There was another dish in its hands.

Under magnification, that dish contains a smaller bedroom, a smaller sleeping figure, and something enormous pressing one eye against the sky above it.

The figure has just looked up.

So have I.