Its geography was quite varied, with oceans, mountains, cliffs, craters, forests, swamps and even geysers. Animal life included small dinosaur-like reptiles, turtles, monocular cephalopods, a giant six-legged insect, a small stegosaurus-like armored animal, a yeti-like humanoid, and an amorphous creature with five eyes.
In 2266, Ecnal was beset by an unexplained loss of life energy. Plant life withered and animals became listless. A serendipitous visit by the Federation starship USS Enterprise led to an investigation, with James T. Kirk, Spock and Janice Rand exploring the surface aboard the Galileo. Spock's analysis revealed external forces at work, and planetary scanners located the source: an alien Lerow rocket on the surface. The landing party provided its crew with a much-needed energy converter, and they departed gratefully. Afterwards, the officers were treated to a banquet featuring an alien musical quartet, juggling and dancing. (TOS comic: "Planet Ecnal's Dilemma")