Crisis On Infinite Earths #5 (1985)

Crisis On Infinite Earths - Worlds in Limbo
The death of the Monitor has combined Earth-1 and Earth-2 in a limbo-like netherverse. However, the worlds are still threatened. The vibrational frequencies that separate them are slowing, and the two Earths are slowly merging, a process that could prove disastrous if it is not done carefully. What's more, there are still three other Earths remaining, which are essential if the Earths are going to be saved. Harbinger, Alexander Luthor and Pariah gather all of the available heroes and villains from both Earths on the Monitor's satellite to warn them of this threat. Returning them to their merging worlds to see the consequences of their situation, they are told to decide quickly whether they will aid in combatting the anti-matter threat.
Release Date: 1985