Four soldiers arrive to take out a dictator and enter a cave filled with skulls and marked "Beware." They find a purple gem but are attacked by an old man named Mophir. They capture him and he warns them not to touch the "Black Heart." One of the soldiers takes the stone, which possesses him – he begins whistling a strange song then shoots down his comrades, blows up the cave, and leaves. Mophir survives but claims "it's the end of the world." The soldier goes off to find a missile base and use its weapons to destroy the world. He's captured, but the base's general takes the gem and starts acting in the same manner, stealing an energy suppressing device.
Meanwhile the Flash is making commercials and drawing the anger of both Green Lantern and the public via a talkshow host, Glorious Godfrey. When the Flash quits doing commercials his agent starts working with Godfrey and the general sees the TV report. He dons a purple costume and fights the League – Wonder Woman defeats him and picks up the stone, and starts humming the same tune.
In the comics "Eclipso" is a demonic creature (first appearance House of Mystery #61, July-August 1963) who possesses a scientist named Bruce Gordon after he scratches himself on a black diamond. In this modern-day Jekyll/Hyde, Eclipso the demon emerged during eclipses and could be driven back by bright light. Eclipso wore a costume similar to that which the general wore in this episode, but the name "Eclipso" is never used in this episode and the serpentman origin given here is entirely unique. This is his first appearance in the WB animated universe.
In the comics Godfrey is a charismatic villain from Apokolips working for Darkseid (first appearance Forever People Vol 1. #3 - June-July 1971). In the Legends mini-series he took the role of a talkshow host and turned the public against superheroes. Clearly here he has no such background, since Darkseid probably wouldn't leave him around after failing so badly. This is his first appearance in the WB animated universe.