identify this strange nut

Cable is 3" longer than usual (like the long Frost nuts), the nut itself has less taper to it than anything else in this size range and a very, very subtle concave/convex aspect on both the large and end faces. Unusual swage completes the picture. I'm thinking it's Eastern European.

Mike, when you can't identify it, I know it's an oddity.

Where'd you find it?

Bootied. Happy to return to the owner if possible.