I have no idea what this thing is, and it appears to be a kitchen tool, but for what?
I put up a YouTube video of it, and would love to see if anybody knows exactly what it would be used for, because we have no idea:
It would appear to be some kind of corer, or to cut shapes out of some fruit, but I can't find anything similar to it online.
The video linked to above does a better job of showing it from multiple angles.