Can the JLA defeat a villain who can become the entire JLA?
The story: "The Triumph of the Tornado Tyrant!" by Gardner Fox, Mike Sekowsky, and Bernard Sachs. A strange creature known as the Tornado Tyrant is convinced it can defeat the Justice League since it has been studying them and even duplicating their abilities by creating anti-matter versions of the JLA. But of course the JLA figures out a way to outsmart the creature!
Roll Call: Superman, Batman Wonder Woman, Aquaman, Flash, Green Lantern, Martian Manhunter, Green Arrow, The Atom
Notable Moments: Features cameos by Adam Strange, Kanjar Ro, and Dr.Light, as the Tornado Tyrant watches the JLA from afar in their battles. A fun touch.
This issue is also memorable to me because a sequel of sorts was done twenty years later in JLA #s 192 and 193 by Gerry Conway and George Perez. It adds so much to this story with that knowledge in the back of your head.