Pot: 7 cm.
Also commonly called "devil's head", it is a globular cactus with a slow growth and a solitary habit, which can cluster over time. Its body is of a bluish-green color tending to gray, slightly concave at the apex, where, over time, a thick white down similar to a pillow is formed. It has many well-furrowed ribs, equipped with numerous downy areoles of a white-yellowish color. Its spines are particularly long and robust, of a very dark brownish-red color; their peculiarity is that with growth they become very large, of a flattened shape, tending to become black, intertwining along the ribs. Flowering occurs in spring only on large plants, blooming with many small red-pink flowers that form a ring at the apex of the plant.