Dr. Eugene Ross invented the world’s first autonomous self-replicating nanites.

He sat at his patio table with his laptop while wondering what project to give them. He gazed at the weeds in his lawn. He thought to himself, “Why not make the nanites the most environmentally safe weed killer?”

He programmed the nanites with a simple set of criteria to eradicate the weeds in front and back.

————

For weeks his lawn looked pristine until one morning when Eugene woke up and went outside to get the daily newspaper. A decomposing human corpse laid in his front yard, and a whimpering dog sat next to its owner’s body.

Eugene called the police. They mentioned the person likely died from a heart attack, and then the coroner took the corpse to the morgue.

No one spoke of the body’s unusual state of rapid decomposition.

Eugene volunteered to foster the dog.

Later, in the evening, Eugene sat on his living room couch and watched TV with his new canine companion ...

“Breaking News! This is Sam Jenkins ...

“Lifeless bodies are being spotted everywhere at golf courses, public parks, forests, and in every green space. We’ve received several eye witness reports about dog parks and pets roaming around their deceased owners.”

Eugene loaded up the nanotech controller software.

As the logs confirmed, he instructed them using natural-language processing: protect the grounds, stop invasive species, sustain the ecology, maintain the green, prevent parasites ...

“Shit!” He gasped when he scrolled to the last line—observe and learn.

He attempted to retrieve data directly from the nanites, but they denied his access.

From that point on, Eugene allowed the dog to walk on his property lawn. He couldn’t step on it himself—each time he set foot on the grass, a grinding and crackling noise emerged, and the surface morphed with a reactive intelligence.

————

For the rest of his life, Eugene kept his nanite invention a secret. The world outside became lush and overgrown with greenery, and the air quality cleared up to pre-industrial levels.

Movements became heavily restricted for humans—they could only travel on ever-crumbling infrastructure, sidewalks, pavement, or barren hiking trails.

Anything botanical would kill ...

Civilization as a whole, reverted to primeval behaviors. To survive, people resorted to foraging whatever fell or rotted from the plants and trees, or scavenging already dead animals, and only at a safe enough distance under timed observations.

As to Eugene, he felt no remorse—instead, the exact opposite.

He proudly watched as his nanotech weeded the environment.