The Shadowhorn, or "morchaithras", was a large, flat, black ray equipped with a long, whiplike tail. Its tail was studded with short but exceptionally sharp barbs that delivered knifelike cuts and injected victims with a powerful muscle venom. The giant ray's expanded pectoral fins formed triangular wings that extended along its head and trunk, giving the fish a diamond shape. The tips of these wings were equipped with electricity-producing organs that could stun or immobilize a swimmer.