Justice League of America #55

The JSA, with new member an adult Robin, confront and are defeated by four normal persons on Earth-2, powered by black matter from another universe. When they ask for help from the JLA using Johnny's T-Bolt, he brings them a battered JLA team, suffering the same problem as their counterparts. Both groups them learn the black matter's origins, and resolve to end the problem on Earth-2 first, lest both worlds be destroyed.