I have tracked Behemoths for nine years. I know their routes, their schedules, their behavioral patterns. I know the sound of their locomotion from three kilometers away — a deep, rhythmic concussion that you feel in your sternum before you hear it in your ears. I know they are machines. Autonomous, yes. Complex, yes. But machines. I have always known this. After July 3rd, I know it less.

I was tracking Behemoth M-17 — a medium-class unit, approximately 40 meters at the shoulder, following its standard summer migration route along the former I-94 corridor. M-17 is predictable. It walks. It does not stop unless it encounters infrastructure that requires routing adjustment. It does not deviate. It does not interact with observers. I have tracked M-17 fourteen times. It has never acknowledged my presence.

At 16:47 on July 3rd, at grid reference 41.7824N 87.6109W, M-17 stopped. Not slowed — stopped, mid-stride, with one forward leg suspended approximately 8 meters off the ground. The cessation of the locomotion vibration was so abrupt that my inner ear misinterpreted it as an earthquake. Then M-17 turned. Behemoths do not turn. They adjust course gradually over hundreds of meters. M-17 rotated its forward sensor array approximately 90 degrees and oriented directly toward my observation position, 1.2 kilometers away. It saw me. Or whatever a machine does instead of seeing.

Then it made a sound. Not its locomotion sound. Not a mechanical noise. A sound that came from somewhere inside its chassis that is not documented in any technical specification I have ever read. The sound was low — subsonic, mostly — and complex, and it lasted for approximately four seconds. In those four seconds, I heard my mother's voice. Not a recording. Not a facsimile. My mother's voice, saying my name the way she said it when I was small and she was calling me in for dinner. My mother has been dead for six years. M-17 does not have speakers. M-17 does not have a voice. And yet I heard my mother, and I sat in the grass and cried while a forty-meter machine stood still and watched me, and then it put its foot down and walked on, and it has not acknowledged me since.

I do not know what happened. I do not know how a machine produced my mother's voice. I do not know why. I am continuing to track Behemoths. I have not told anyone about this until now. I am writing it here because I need it to be somewhere other than inside my head.