Cereus aethiops grows shrubby, is rarely branched and reaches heights of growth of up to 2 meters. The cylindrical, dark bluish to dark green shoots are upright, occasionally prostrate and have a diameter of 2 to 4 centimeters. There are seven to eight ribs that are divided into humps. The
areoles on it are often almost black. The two to four black central spines are up to 2 centimeters long. The nine to twelve radial spines are gray with a darker tip or black. They reach lengths of up to 10 millimeters. The white to light pink flowers are up to 20 centimeters long. The egg-shaped, red fruits are up to 6 centimeters long. File:Cereus aethiops 1.jpg|Fruit File:Cereus aethiops 2.jpg|Plant growing in the wild climbing on
Geoffroea decorticans at Colonia Cilavert, Las Grutas, Río Negro province, Patagonia, Argentina File:Aethiopsbloom.jpg|Flower of cereus aethiops ==Distribution==