We rented a beach house in the Outer Banks last week. The kitchen was pretty well-stocked with cooking gear (12 sets of crab crackers!), but this one item left me completely stumped. I took photos of the front, back and an angle so you can see the inside. It screws down to clamp something in place, but to what purpose? It's far too large to be a cherry or olive pitter (about 4" long), and it would seem unnecessarily complicated as an egg slicer.
I'm hoping someone else will recognize it.