Octasphericon (octagonal sphericon)

thingiverse

You're meant to print out two halves of an octasphericon, also known as an octagonal sphericon. They join to make the object, which rolls in an unusual way. A middle connector is required. Note that this object does not roll well, unlike its six-sided counterpart. The hexasphericon will roll smoothly enough, but the octasphericon won't roll unless it's on a very slight gradient slope - more for visual appeal than any other reason.