Twice-Told-Tales: Ancient Alien Adversaries VS Awesome Avengers

Ancient alien adversaries attacked Earths One and Two in the 20th century, aeons after making their first appearances thousands of years earlier, when they devastaed rival races on other worlds. The celestrial bodies these beings called home consisted of an intruding planetoid and a yellow comet, which jeapardized the safety of the worlds they orbited. Only the combined might of the Justice League of America and Justice Society of America could tackle the threats possessed by the citizens of Luna and denizens of the comet!

In 1978, the mysterious satellite known as Luna first materialized above Earth-One. As a result, vast natural disasters occurred around the globe, facilitated by the gravitational pull of Luna. As members of the League were dispatched across the planet to help mitigate the effects of this, while saving victims left in their wake, the Leaguers encountered the invading inhabitants of Luna. The League members (Green Lantern, Flash, Atom, Wonder Woman, Black Canary, Superman, Batman, Aquaman, Green Arrow, Elongated Man and Red Tornado) discovered from testimony provided by the adversarial aliens' governor that the planetoid Luna was known as Regina, and it had shifted from its own dimension into that of Earth-One. As before, Regina derived energy from Earth-One which helped sustain its existence and that of its inhabitants. 

In 1949, a mysterious yellow comet along with meteors entered the atmosphere of Earth-Two. As the trio of meteors landed only in locations within the United States, the global impact was confined into smaller regions, although various fires was ignited at each point of impact. As a result, three teams of Justice Society are dispatched to three areas where the meteorites have landed to assist the local inhabitants while quenching these fires.  At each destination, the Society members (Green Lantern, Flash, Atom, Wonder Woman, Black Canary, Hawkman and Doctor Mid-Nite)  encountered the Fire People originating from the comet, each attempting to and succeeding in procuring valuable stores of radium from their human foes.

The JLAer soon discovered that Regina and its people existed millions of years earlier, and had been shifted forward in time following an intra-solar system battle with another planet, which they destroyed, Fragments of that doomed world became the astroid belt now existing between Mars and Jupiter, while the energies unleashed thrust Regina into the 1978. The Justice League used their combined powers to propel Regina into a far-future time period, where it would orbit an uninhabited Earth-One.

The JSAers soon discovered from an ancient recording that these comet-people had arrived millions of years earlier, and destroyed humanity of that era using radium they had stolen.  Equipped with this knowledge, the Society ascertained that white-heat could drain the Fire People of their strength. Confronting the Comet-People, who were developing a weapon to erradicate humanity, they were overpowered by the Society and their heat-projectors. Rather than submit to being captured, the Fire-Being turned the weapon upon themselves, destroying their once proud race.

These were but two examples of several encounters the League and Society had with alien invaders. Other invasions from above which their Worlds' Greatest Heroes were able to thwart included the Appellaxians and Yzgartyl, Starro and Nyarl-Amen, the android Manhunters and Diamond Men, the Dronndarians and Golden-Men, the Treasurers and Green-Heads, to name but a few.