Thanks! What a wild object. I wonder where the seller picked it up from.It's part of a stereotaxic alignment device from a veterinary research laboratory, used to determine the positioning of electrodes in the bodies of test animals. The clue is the manufacturer, David Kopf Instruments, which specializes in such equipment.
Be a good piece for decorating a Frankenstein lab for Halloween, but don't let any cat, dog, rat, or monkey see you coming with it.