In the winter of 2015, I had strange recurring dreams that involved my mother. She had been dead for 12 years. In the dreams, she was mysteriously alive and wore an ankle-length, floral-print, sea-green gown with white eyelet lace around the wrists and neck.

The visions would come about like this: I would turn off the light in the master bedroom of my Columbia City house, think of this and that in the dark for a few minutes, and then, without warning, slip into a new episode of the dream. The house in the dream was a combination of the house of my rural childhood in Sharptown, Maryland, and the house of my teenage years in Harare, Zimbabwe.

In the dream, I'm in the house doing something that's uninteresting: cleaning dishes, watching a baby, or talking to my mother, whose bedroom has six beds. All seems fine.

In one dream, I even danced with her. Our last dance in the real world was in 2002, to Brenda Fassie's devastatingly beautiful "Vul'indela." This took place in the living room of my Columbia City house. In the dream, which occurred in 2015, the tune was "Under the Pressure" by the band the War on Drugs.

These dreams were not innocent for long. By 2016, I sensed in them a growing and deepening dread. At first, I thought it was the realization that the mother in these dreams was not alive. I would look at her: She was either on the phone talking to her older sister, Della, or sitting—legs crossed and a brown cozy slipper dangling from the toes of her raised foot—on a brown folding chair under a skylight that never existed in the houses in Harare or Sharptown. This ghost of her meant no harm. She was just happy to be out of the void of death that imprisoned her when I was awake in the real world.

But around this time, in 2016, a new element was added to the series of dreams: a basement.

I had no idea what the basement corresponded to in the real world, but it was always accessed from the kitchen of the dream house. There was a double-hung window above the sink, a chrome-plated retro dining table and four matching chairs, a General Electric fridge, and next to that a plain door that opened to a long set of concrete steps that led to a basement.

Curious, heavy with dread, I decided to walk down to the basement. There I found the presence of an evil that was concentrated and coldly alien. It was not an animal hiding in the dark with red eyes and sharp teeth. It wasn't satanic, or anything like the demon in the famous Amityville house. It was not one thing, nor was it many things. I could not see it. But it had a smell. The closer I got to it, the more musky and musty it became. The evil was by a few sacks of rotten potatoes, and beneath me, and behind me.

Every time I returned to the dream, the power of that thing grew. I no longer had to enter the basement to feel it. In one dramatic dream, I realized the baby (now a boy and, as it turned out, my son) had opened the kitchen door and entered the basement. It was fine for me to go down there (I could always wake up and the basement would no longer exist), but I knew no one else in the dream should, not even my dead mother, who was less and less present in these dreams.

I weirdly knew it would never harm me, whatever it was that was in the basement, but I was not sure what it would do to other visitors, this monstrous thing. I went down the concrete steps and entered the dark, looking for my son. I passed the bags of potatoes. I passed a black support pole. I sneezed and saw there was a door on the far side of the basement. I felt evil all around me as I walked to this door I had never seen before, thinking my son was behind it.

Before reaching the door, I felt my son was behind me. I turned. There he was, looking at me like he had never done before. I ran to him. I grabbed his wrist and pulled him up the steps.

Then something terrible happened.

As we reached the top of the concrete steps, I realized that though the boy looked like my son, he was not. I let go of his wrist and woke up. It was 3 a.m. My wife was on the other side of the bed. Her dreaming breathing was smooth. My real son was in his room. I checked on him. He was bundled up in blankets and fast asleep. I did not want to go back to sleep because I knew I would return to his other, the evil boy on the steps.

I finally decided, for the sake of my sanity in the real world, and out of fear that the evil in the dream would begin affecting my family life, to confront the basement monster.

To get it out of my dreams, I needed to know what it was. I took three Advil PMs, drank a glass of red wine, turned off the lights, and placed my head on three stacked pillows.

I was back in the basement. My real son in the dream world was still missing. The evil one sat in one of the chairs in the kitchen. My dead mother refused to leave her room. A moment later, I was in the middle of the thing. I demanded to know what it was.

Now, this is hard to explain. But the thing told me a story. Not in words, but in images. It was not from earth but was a vector of vacuum deep in space. I asked it to explain what it meant by vector of vacuum. It showed me nothing. Just nothing.

But how did it get here, into the basement? It was the presence of an utter emptiness that somehow found itself in a world filled with the stuff of dreams. The vacuum only wanted nothing: no light, no phantoms, no dreams.

And this no-thing is the ultimate horror. I understood then what it is we fear most about death. It is the ultimate paradox. You can know death, but death can never know you. You can think about death, but death cannot think about life. What this means is: In death, you never existed at all. The nothing in death fuses with the nothing before life. And nothing becomes all there ever was. To exist is only to exist. To not exist is never to have existed.

But I was still alive. And I was dreaming.

The vacuum in the basement suddenly vanished.

I knew it was gone, no longer there. I awoke—it was 4 a.m. I had a glass of water and looked out the window by my bed. Still dark. The no-thing has never returned to the house of my dreams.