420356 Praamzius, provisional designation 2012 BX85, is a trans-Neptunian object from the classical Kuiper belt, located in the outermost region of the Solar System, approximately in diameter. It was discovered on 23 January 2012, by astronomers Kazimieras Černis and Richard Boyle with the Vatican's VATT at Mount Graham Observatory in Arizona, United States. The cold classical Kuiper belt object is a weak dwarf planet candidate and possibly very red in color. It was named after the chief god Praamžius from Lithuanian mythology.