Echidnopsis malum is a small succulent with grey-green or brownish stems, up to 15 cm long or sometimes more, the angles rather indistinctly divided into low rectangular tubercles. The flowers are shaped like an urn, held upright, depressed at the apex and with a pentagonal opening about 4 mm wide. Outside bright green with red streaks, inside dark purple-red and in lower and upper parts with long white hairs, the middle portion somewhat tuberculate. The transverse wrinkling of the corolla-tube is also remarkable, being more pronounced than in any other species. The corolla-lobes are triangular-ovate, about 4 mm long, very fleshy.