The “Gomboc” is a mono-monostatic object, a three-dimensional thing that has only one way to stand up. Like a weeble, you might offer. (I’d be right there with you.) But apparently, no. While a Weeble could in theory be balanced on its opposite, egg-shaped side, the Gomboc is only stable at a single point. It is therefor always self-righting. (Plus, the Weeble rights itself because of extra weight in its ample bottom, while the Gomboc is the same density throughout.)
The scientists who discovered the Gomboc shape are now selling acrylic versions of the same online, each with a special serial number and certificate. Unfortunately, each one starts at €900, with an additional cost based on its serial number. Seems a bit over the top for what is ultimately just a lump of plastic.