This is one of the strangest looking craters ever found on Mars, and this platypus-tail-shaped depression, called Orcus Patera, is an enigma. Orcus Patera is a region on the surface of the planet Mars first imaged by Mariner 4. It is a depression about 380 km long, 140 km wide, and about 0.5 km (500 meters) deep but with a relatively smooth floor. Elements of this video furnished by NASA. Zoom Out. Full HD.