Warning: The following feature contains SPOILERS for Crisis on Infinite Earths.
The final two chapters of the Arrowverse adaptation of Crisis on Infinite Earths were again packed with Easter eggs and references, and were perhaps the closest in content to the original comics. The fourth and fifth episodes of the crossover event also drew off of a number of other classic stories in shaping their climactic battle to save all reality from the Anti-Monitor.
Things looked bleak at the end of "Crisis on Infinite Earths - Part 3," with apparently only seven beings (the so-called Paragons) having survived the destruction of the positive matter universe. Thankfully, an old ally had also survived the cataclysm by, as he had once before, becoming something else. Now wielding the power of The Spectre, Oliver Queen was able to guide the Paragons to where they needed to go in order to rebuild reality.
The final episode of Crisis on Infinite Earths revealed a reborn Arrowverse. Unfortunately, the Anti-Monitor had survived his apparent defeat, requiring an assemblage of heroes unlike any seen before to forces and save the new multiverse. Here's the rundown of every single Easter egg hidden in Crisis on Infinite Earths: Parts 4 & 5.
The Planet Maltus
The prologue of "Crisis on Infinite Earths - Part 4" was set on the planet Maltus, some ten thousand years in the past. Maltus was revealed to be the home of Mar Novu - the alien scientist who would, in the future, become Green Lantern Corps.
The Legend Of Krona
The prologue of "Crisis on Infinite Earths - Part 4" revealed that Mar Novu and his wife Xneen were attempting to send him back to the dawn of time so that he could observe the creation of the universe. Unfortunately, Mar Novu's presence in the Temporal Zone triggered a release of strange energies he later identified as anti-matter and broke the barrier between the positive matter and anti-matter universes. This attracted the attention of the Anti-Monitor and set him upon his plan to destroy the positive-matter multiverse born of Mar Novu's mistake.
The original Crisis on Infinite Earths comics told a similar story, which was a revamp of an older story first told in Green Lantern #40 in 1965. It was here that a scientist from the planet Oa named Krona became obsessed with observing the beginning of the universe, despite a legend among his people which spoke of disaster should anyone ever try to watch the universe being created. Krona's experiment, which originally released evil into the universe, was retconned to have also triggered both the creation of the anti-matter universe and a multiverse of infinitely replicating realities. Apart from Krona being replaced with Mar Novu and Oa becoming Maltus, the final chain of events was precisely the same in both versions of Crisis on Infinite Earths.
The Monitor's Armor
While earlier episodes had poked fun at the Monitor's distinctive armor, "Crisis on Infinite Earths - Part 4" did offer an explanation for it. As he prepared for his first trip through time, Mar Novu dryly asked his wife if the suit she had designed for him was "the height of fashion at the dawn of time." She responded that he needed protection from coronal radiation and the bulky if unaesthetic materials composing the armor would provide that protection.
Vanishing Point and Zero Hour
When the story of "Crisis on Infinite Earths - Part 4" returns to the modern day, it finds the Paragons trapped in Vanishing Point; a dimension outside of time and space, which was once home to the Time Masters before their defeat at the hands of the Legends of Tomorrow. In the comics, Vanishing Point was the base of operations for a similar group of time cops known as the Linear Men, who were not introduced into the comics until several years after the conclusion of Crisis on Infinite Earths.
The Linear Men and Vanishing Point played a major role in Zero Hour: Crisis In Time; a 1994 mini-series and follow-up to Crisis on Infinite Earths, which was intended to correct some of the continuity problems that had arisen in the decade after Crisis. Battling a new villain called Parallax who sought to destroy the universe and rebuild it according to his own design, the Linear Men gathered a team of heroes they determined could stop Parallax and assembled them at Vanishing Point. This was similar to what happened with the Paragons in the Arrowverse.
The Spectre Rallies The Troops
In Crisis on Infinite Earths #10, The Spectre broke up a battle between the heroes and villains of the five remaining Earths in the positive matter universe, telling them that they must forces in order to defeat the Anti-Monitor and save their respective worlds. The Spectre then divided them into two groups, guiding one to the dawn of time to stop the Anti-Monitor from destroying the multiverse in its infancy, as the other team went to the planet Oa to try and stop Krona's disastrous experiment. The exact same thing happened in the Arrowverse Crisis on Infinite Earths, with Oliver Queen dividing the Paragons for a two-pronged attack.
The Flash Of Two Worlds
As The Flash traveled through the Speed Force, searching for his lost allies on the way to the dawn of time, he encountered another version of The Flash; a Barry Allen he had never met before. While this has happened several times in the past, this was the first time that The Flash of Earth-1 had encountered his doppelganger from the DCEU. While it was never explained just how another version of The Flash was running around with the Arrowverse destroyed, the cameo by Ezra Miller was perhaps the most unexpected surprise of the crossover event.
Lex Luthor And The Journey To Maltus
Lex Luthor led the villains of five Earths to the planet Oa to stop Krona's experiment in Crisis on Infinite Earths #10. In the Arrowverse, the Lex Luthor of Earth-38 also took the lead in the race to stop Mar Novu. Of course Luthor being Luthor he had an angle and attempted to persuade Mar Novu to let him help shape the multiverse that was to be born of his experiments. Ironically the Lex Luthor in the comics made an honest go of playing the hero during the attack on Oa, though his army ultimately failed in their objective.
Chest-Busters And Predators
After arriving on Maltus, Lex Luthor broke away from the rest of the group to begin scouting the lay of the land. When Supergirl caught up with Lex and demanded to know why he had wandered off on his own, Lex pointed out that they were on a potentially hostile alien world and that "any number of chest-busters and predators could be lying in wait." While most comic readers wouldn't think about Lex Luthor being a film buff, it's telling that he'd reference two science fiction franchises - Predator - which reflect his view of all extraterrestrial life being monsters to be fought against.
Quantum Leap
As Barry continued his travels through the Speed Force, he emerged in a memory of Laurel Lance deciding to become the Black Canary in the wake of her sister Sara's death. Suddenly finding himself facing a John Diggle and Laurel Lance who had not yet met him as The Flash, a stunned Barry quietly muttered the words "Oh boy." This seems to be a nod to the classic time-travel series Elseworlds, which had a running gag involving Quantum Leap and Barry Allen being a fan of the show.
The Brave And The Bold
As Lex Luthor persuaded Mar Novu to let him help him with his experiment, Lex jokingly referred to their team-up as "The Brave and the Bald." This is a nod to a classic DC Comics series, The Brave and The Bold, which was devoted to team-up stories, typically involving Batman and another superhero. The series is historically notable for hosting the first appearance of the Justice League and it later inspired the Batman: The Brave and The Bold cartoon.
