What's this Justice League (cartoon) episode called and where can I view it?

It was a cool episode involving some evil guy who travels back and forth through time as his "evil super power". The end was pretty cool because he started to travel back in time to the beginning of time to make himself a god, but the green lantern and someone else get into the time warp with him and stop him before he can make it, and then all's good and whatnot... Anyone know? Thank you