Specimen: the reflective plane.
The colony affixes a polished sheet to a vertical surface at a height calibrated to the organism's optical sensors. The sheet emits no light of its own. It returns light, faithfully, producing a duplicate of whatever stands before it, inverted along one axis.
The organisms approach it in a predictable behavioral loop. The human halts. It faces its duplicate. It then performs a series of adjustments not to itself but to its outer keratin fibers, its fabric coverings, the arrangement of its facial soft tissue. It rehearses expressions. I have logged a human produce, in sequence, four distinct configurations of the mouth, discard all four, and depart with a fifth it had not tested.
Correction to earlier hypothesis. I first classified the plane as a predator-detection device: the organism confirming no second entity approaches from behind. This is incorrect. The organisms know the duplicate is not real. They mount these sheets in the chamber where they excrete, in the chamber where they sleep, in the small mobile carts they ride. A species does not surround itself with false rivals by accident.
The true function is confirmation. The human requires periodic proof that it continues to exist and has not, since last inspection, deformed. It leans close. It examines the thin creases accumulating at the eye sensors, touches them, and its face performs a downward slackening I cannot yet classify. Some malfunction of the tissue. It happens only at the plane, never elsewhere.
I note the organism does not thank the sheet, nor mourn when it is covered. It simply requires, several times daily, a surface willing to insist that it is there.
I have requested one for my own quarters.
I wish to determine what, precisely, it will insist about me.