9. Possessed By The Society - Justice League Of America #166-168 (1979)
The Secret Society of Supervillains is a generic evil group, much like the Legion of Doom or the Injustice League. The Society are usually not considered a major threat but they came very close to destroying the Justice League in in the three-parter, The League That Defeated Itself.
After The Wizard discovered a mystical griffin statue that swaps minds into other bodies, he realised the easiest way to defeat the Justice League was to become the Justice League! Using the statue on the superheroes, Wizard swapped minds with Superman, Blockbuster with Batman, Reverse-Flash with Green Lantern, Star Sapphire with Zatanna, and Floronic Man with Wonder Woman.
Not only did the Society parade around as superheroes, vigilantes like Red Tornado and Green Arrow kept attacking the League, since they were trapped in the bodies of supervillains. To make the situation worse, the Society unmasked themselves so they could learn the secret identity of each Leaguer.
When Green Arrow and Black Canary noticed how inappropriate their "friends" were acting, they deduced the Wizard and his underlings had possessed the League. Using her magic, Zatanna returned everyone to their original bodies and erased the Society's memories of the whole event.