Disc of Sabu
The Disc of Sabu was found in the Tomb of Prince Sabu, son of Adjuib Pharaoh ouf of I Dynasty around 3000BC.
No proper explanation has been given for this mind twister.
Different technical studies have given results of a "fuel mixer". But independently of what the object was supposedly used as/for, the imperfection of its design and stone work (schist is so fragile that minerals grain and split off easily into flakes or slabs) highlight the fact that it is more likely a stone copy of an older perfectly shaped metallic object, yet to be determined.
History books refer it as a Traditional Egyptian bowl/vase.