Fishing lure. You will need to add an appropriately sized split ring and a treble hook before you can catch anything.
This is the thin and lighter version of the lure with a minimum wall thickness of approximately 1.1 millimeters. A thicker and heavier version can be found at the following
link:
https://www.shapeways.com/product/ZQ5F4774V/fishing-lure-octagonal-bumps-thick?key=c56a32633baba82c90cd6b0806522d13