We found it in Tunnel Section 77-D, approximately 900 meters below the Shelf waterline, in a passage that does not appear on any infrastructure map. The passage itself is anomalous — it is older than the tunnel system it connects to, based on geological stratification of the surrounding rock. The tunnel was bored through limestone that has been undisturbed for approximately 4,000 years, based on calcite deposition rates. The machine at its center has been running for longer than that.

The device is approximately two meters tall, one meter wide, and constructed of a metal that resists all non-destructive analysis. We cannot identify the alloy. We cannot scratch it. A small hopper at the top accepts objects — stones, screws, coins, whatever is placed inside. The objects disappear into the mechanism and are deposited into one of 144 output bins arranged in a 12-by-12 grid on the device's face. The sorting criteria are unknown. A steel ball bearing and a glass marble were placed in the same bin. A second steel ball bearing, identical to the first, was placed in a different bin. A dead beetle and a quanta coin were placed together. A live beetle was placed alone.

The device operates continuously. When no objects are provided, it sorts dust and air particles — the output bins accumulate fine residue in patterns that suggest the device is sorting ambient particulate matter by the same unknown criteria. It produces no sound. It generates no heat. It has no power source we can identify. It has no seams, no fasteners, no access panels. It is a single object. It was not assembled. It appears to have been manufactured as a continuous piece.

We placed a tracking sensor inside the hopper. The sensor was sorted into bin 37. Its telemetry data shows that the interior of the machine is larger than the exterior, which is not possible. The sensor recorded 4.7 seconds of travel time through the interior, during which it covered an apparent distance of 340 meters. The machine is one meter wide.