Corrupt Chronol Clones Cause Cosmic Crisis

The sinister scientists and aspiring authoritarians, T.O. Morrow and Per Degaton, each borrowed technology allowing them to pierce back the veil of time. Borrowing from the intellectual advancements of other more honorable men, Morrow and Degaton. 

Futurenergy helped formulate five chronal clones based on five love interests of the Justice League, in order to ensnare half of its membership. These were Steve Trevor, Jean Loring, Shayera "Hawkgirl" Hol, Midge, and Mera... whose identical appearance to the originals helped lure Wonder Woman, the Atom, Hawkman, Snapper Carr and Aquaman into kissing them. This caused each Leaguer to fall into a comatose state, leaving the remaining members to face automatons replicating old adversaries of the League. Among these, there was a sixth chronol duplicate who appeared in Doctor Light. Once each served his or her purpose, they were promptly erased from existence, while the original five romantic partners of the League were unaware of what transpired to the loves of their lives.

Temporal causality from Per Degaton's time machine, which he stole from Professor Zee, allowed him to pull sixth supervillains from the late 1940s back to December of 1941. These included Per Degaton himself, Wotan, Professor Zobar Zodiak, Sky Pirate, King Bee and the Monster (a seventh cloned creature, Solomon Grundy, was actually the doppelgänger of the Earth-One Solomon Grundy spawned by the Parasite decades later). Due to chronol energy, these crooks were able to exist simultaneous to their younger selves, who were existing in the same time period unaware of these events transpiring. All of these criminals except the Monster were able to ensnare their prey, leaving all save three members of the Justice Society in a comatose state*.

Eventually, thanks to the intervention of the Red Tornado who helped revive the Justice League, and Robotman along with the All-Star Squadron who helped rescue the Justice Society, both Morrow and Degaton were decisively defeated. As with Morrow's clones, Degaton's clones** were each erased from existence as they resumed their lives in the future from which they were originally plucked.

* The ensuing battle between the All-Star Squadron and Justice Society versus Degaton's minions mirrored the battle on another occasion between the Justice League and Queen Bee's Anti-Justice League.