Monolith of Evil

Solomon Grundy convinces The Legion Of Doom to pursue a monolith that is supposed to be the source of all evil and gave him powers. So he, Cheetah, Riddler & Grodd search under the Earth's crust for it after the Hall of Doom is used to burrow through the Earth, but it is defended by a lava monster. Unable to achieve their goal, they decide to trick the Super Friends into retrieving the monolith for them. After Hawkman, Black Vulcan & Superman obtain the power source, Grodd the Gorilla incapacitates Superman with a kryptonite chain and ball which is attached to Superman's leg and seals them in the underground inferno. While the Legion of Doom wreaks havoc upon the east coast, Apache Chief, Green Lantern and Flash rescue their trapped teammates, and Green Lantern cuts Superman free. Wonder Woman, Batman & Robin launch an attack on the Hall of Doom which is protected by the monolith, which produces a water monster. Batman uses the Batplane's freeze ray on the monster, but another beam from the monolith allows it to move. The Hall of Justice computer reveals that the monolith is not evil, it just appears that way because it is being controlled by evil beings; this gives Wonder Woman the plan to control it telepathically to do good. After reversing all of the destruction and apprehending the Legion of Doom, the Legion uses the monolith one last time to escape.