From 2.0 to 2.3 inches long, the unicorn clubtail has a gray-green thorax with black shoulder stripes. The abdomen is mostly black with pale dorsal stripes, and with fringes of the clubtail rusty brown and the end yellow. The legs are mostly black, with pale streaks on shins and sometimes on thighs. The eyes vary from gray-green to bright green.
Found in eastern US, from Tennessee northward to Ontario, the unicorn clubtail prefers ponds, lakes, and slow streams with muddy bottoms and little submerged vegetation. At lakes, they seem to prefer inlets. Wisconsin is at the western edge of the range. It is only known from a site in Sheboygan County.
Throughout its range, the flight season is from early May to late August. In Wisconsin, they have been found in late June and July.