Mastermind

Mastermind was an alien supervillain who learns the secret identities and weaknesses of all of the Justice League, and plots to destroy them.

History
Mastermind informs five members of the Justice League that he knows their secret identities, and tells them if they do not meet him on Black Mountain he will expose their secrets. This lures Superman, Flash, Atom, Green Lantern and Hawkman to Black Mountain, where Mastermind then reveals himself, and tells the League of his evil plans to destroy Metropolis and other places on earth, so that he can rule the world. When Superman, Flash and the Atom attempt to stop him, they are teleported to his asteroid headquarters, where Flash and Atom are contained in a force field and Superman in a kryptonite cage. Green Lantern and Hawkman arrive in the Hawkship and rescue Superman, Flash and Atom. And Mastermind escapes in his space ship, but only after setting the asteroid on a collision course for earth. After the rest of the Justice League leave the asteroid, Superman stops the asteroid from crashing into earth, by deflecting it into Mastermind's space ship, which kills the villain and ends his threat to mankind.

Appearances
The Superman/Aquaman Hour of Adventure
 * Bad Day on Black Mountain