M. booli in its varied form is much sought after by collectors because the variegation offers the plant a unique and unmistakable appearance. It has a soft and green stem, creating a perfect contrast with the yellow of the variegation; conical tubercles, at the apex of which form woolly white areoles. From the latter come out thick thorns ranging from white to red-brown. In the center there is a red-brown hooked thorn, the central one. Its beautiful flowers bloom at the apex, and have colors ranging from white to pink.