The Ophidians were a race of humanoid snake-like creatures that lived on Earth thousands of years ago and are the main antagonists of the 2-part episode "Eclipsed" of the Justice League cartoon series.
The Ophidians, snakes who walked like men, fought mankind over domination of the planet. They worshiped the moon and preferred the dark over the light. Mankind was winning the battle, and eventually drove the Ophidians to near-extinction. In desperation, the last remaining Ophidians performed an arcane ceremony during a lunar eclipse, sending their souls into a dark gem later dubbed the Heart of Darkness. Anyone who held the crystal would become possessed by the Ophidians' spirits and driven to destroy mankind. Mophir's people dedicated their lives to guard the crystal from falling into the wrong hands.
In the 21th century, human soldiers found the Heart of Darkness and overpowered Mophir, the last of the guardians of the temple. Burns, who had taken the crystal, learned of nuclear weapons and tried to use them, but failed. However, he managed to give the crystal to General McCormick, who had just overseen development of the AFD. Learning of the Justice League, the possessed McCormick drew them to a power plant, where he managed to give the Heart to Wonder Woman. She stole the AFD and smuggled it aboard the Watchtower, handed the Heart to J'onn J'onzz, who unloaded the device before giving the crystal to John Stewart.Having learned of the Heart from Mophir, Flash began using a light-inducing gemstone Mophir had given him on the League, but the possessed John destroyed it. He was subdued and dropped the crystal, but Hawkgirl shattered it with her mace, causing it to explode into shards. The shards became embedded within the skin of all the Justice Leaguers-save the Flash, who was fast enough to avoid the shards.
In addition to hunting the uninfected Flash, the Ophidians who were inside of the League members sent the AFD into the Sun, which would destroy it and doom human kind. However, Flash was able to drive the shards out of the Leaguers with a searchlight, and the Justice League subsequently created a wormhole which drained the damaged matter away from the sun. What happened to the shards is unknown, but they were likely collected and stored away by the League, in order to prevent the Ophidians' legacy from ever resurfacing.
Ophidians have a reptilian snake-like appearance, who have two legs and a tail. They have orange-tannish skin. But when they moved their souls into Heart of Darkness, they all became one army in one stone also lost their physical form. Anyone who touches the Heart of Darkness is susceptible to being possessed by the Ophidian souls within the stone.