This is just a box with a spherical hole in the middle. There is a shaft on top so the hole gets rendered properly. This is for use as a negative space. It is extremely useful for separating heads from the rest of the body from 3D scans using TinkerCAD. Just import it and use it as a hole, position it around the scanned bust so the head fits best inside the spherical hole, and group it and you got the head spliced off.

I've made about 40 scans of family and friends and this makes it really easy to separate their heads from the rest of their bodies so I can do all kinds of deviously fun things with them.