Simple, it's a quasi optical, nuclear powered, dipthong retarder!
It does look to me like part of a car headlight adjuster, the ball end fits into a socket on the headlight shell and the tapered toothed bit is then turned with a philips head screwdriver and the threaded bit moves in or out and adjusts the headlight beam.
These sorts of adjusters are usually accessed through small holes in the metalwork above the headlights.
Regards,
BH.