SPOILER WARNING: This article contains major spoilers for "Elseworlds,” this year's Arrowverse crossover.


The annual Arrowverse crossovers have become a high point in The CW’s DC Comics-inspired superhero lineup, and this year was no different. With the three-part “Elseworlds” event bringing together the heroes and supporting cast of Arrow, The Flash and Supergirl (plus a welcome Legends of Tomorrow cameo), there was plenty of spectacle to satisfy longtime fans and newcomers alike.

Of course, no Arrowverse event would be complete without plenty of Easter eggs for diehard DC fans across all mediums, from TV to movies to the comic book source material itself. That being said, let’s take a look at some of the best Easter eggs “Elseworlds” has to offer.

Smallville Nods

Before the Arrowverse came to be, Smallville was The CW’s premiere superhero drama, so it’s only natural that “Elseworlds” would pay homage to its predecessor. In fact, the crossover wastes no time in doing so by giving viewers a glimpse of the Green Arrow costume worn by Justin Hartley on the corpse of the Earth-90 Emerald Archer during the cold open, which also served as a post-credits scene on last week’s Supergirl.

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However, while fans would be forgiven for not recognizing the costume, there was no mistaking the sound of Remy Zero’s Save Me – the song that kicked off each episode of Smallville for 10 straight seasons – which played when Barry and Oliver traveled to the Kent Farm on Earth-38. And if the Kent Farm and house looked familiar, that’s because they were the very same ones used on Smallville.

Barry’s Lightning Rod

While Barry and Oliver are privy to their rewritten reality from the start of “Elseworlds,” they soon discover they’re the only ones. In an attempt to get through to Iris, Barry (who she believes is Oliver) tells her that she’s his lightning rod, and while this doesn’t undo the effects of the Book of Destiny, it does give her a reason to trust him.

Barry referring to Iris as his “lightning rod” isn’t necessarily new to the Arrowverse, as he did the same in Season 4’s “Enter Flashtime.” However, the term itself stems directly from the comics – specifically Geoff Johns and Ethan Van Sciver’s The Flash: Rebirth.

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It’s a Crisis

Although we’re getting an adaptation of Marv Wolfman and George Perez’s Crisis on Infinite Earths with next year’s crossover, there was a bounty of references to the highly influential 12-issue limited series in “Elseworlds.” For starters, there’s the inclusion of red skies, which have become something of a staple when it comes to DC’s crises. We first get a mention of them when Cisco attempts to reach A.R.G.U.S. but is unable to do so due to the interference from the red skies and yellow lightning. The Monitor even uses the word “crisis” at the end of Part Two, while Oliver says it in Part Three.

As far as deaths go, we don’t get any of the casualties from the comics. We do, however, hear Superman tell Barry and Kara that he foresaw their demise in the Book of Destiny.

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Perhaps the biggest nod to Crisis on Infinite Earths, though, is when Felicity, Curtis, Diggle and company try to determine who’s attempting to breach into their world. In doing so, they discover it’s John Wesley Shipp’s Barry Allen/The Flash from Earth-90, who appears through a portal much like Barry did when he was trying to reach Batman in the source material.

Then again, one could argue that the most glaring allusion to Crisis comes at the end of Part Three, when Psycho Pirate quotes the source material almost verbatim by telling Deegan, “worlds will live, worlds will die and nothing will be the same."

The Bat

One of the biggest selling points heading into “Elseworlds” was the debut of Ruby Rose’s Kate Kane, aka Batwoman, which meant the Arrowverse would finally start acknowledging the Batman mythos outside of the occasional “Bruce Wayne” or “Gotham City” name drop. It begins with Oliver whipping up a quick sketch of Wayne Enterprises, and by the time Part Two of the crossover arrives, we’re met with Batman references left and right.

Oliver adamantly telling Barry that he is the original vigilante is a clever way of acknowledging that Green Arrow was essentially created as a Batman pastiche. Then, at Wayne Enterprises, you have Kate telling Barry, Oliver and Kara that the wifi password is “Alfred,” and we even get a glimpse of the Batman ’66 Shakespeare bust in a box in Bruce’s old office.

Of course, no trip to Gotham would be complete without a pit stop at Arkham Asylum. There, in addition to the names of some heavy hitters from Batman’s rogues gallery printed on the cell doors, we also find Nora Fries rummaging through a shelf that includes a handful of Easter eggs. There’s a set of dentures (a nod to The Joker’s chattering teeth?), the mask Tom Hardy’s Bane wore in The Dark Knight Rises and a box with “1994” printed on it, which is the year Batman took back the mantle of the Bat from Azrael (it’s also the year Zero Hour took place, for what it’s worth). It then culminates with Nora assembling her husband Victor’s (aka Mr. Freeze) freeze gun. And while these references alone would be enough to satisfy most Batman fans, there’s also a shout-out to Dr. Jonathan Crane, aka Scarecrow, whose fear toxin infects Barry and Oliver.

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The Gotham excursion closes with Batwoman referring to her and Supergirl as the “World’s Finest,” which, of course, is the nickname of their male counterparts and at one point, the title of an ongoing series.

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The Man of Steel

In addition to the introduction of Batwoman, “Elseworlds” also featured the return of Tyler Hoechlin’s Superman, and there was no shortage of callbacks to his comic book and movie history. The debut of the evil, black-suited Superman (who actually turned out to be Deegan) is the most obvious, but you also have the revelation that Lois and Clark are expecting a child. In current DC continuity, the pair has a son named Jonathan Kent, who Clark dubbed the new Superboy early on in the Rebirth era.

The Christopher Reeve Superman gets plenty of love, too. When Clark first rips open his shirt to reveal the iconic emblem underneath, you get a small taste of John Williams’ memorable score from Superman: The Movie. Then, when Cisco asks who he is, Clark says, “A friend,” much like Reeve’s Man of Steel did in the 1978 film. Finally, in Part Three, Clark presses a piece of coal into a diamond he can use to propose to Lois, which is what the character did for Lana Lang in Superman III.

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Speaking of Part Three of “Elseworlds,” that’s where we finally get to see some of Supergirl’s supporting cast (it is the Supergirl portion of the crossover, after all). Of note, when we’re introduced to the evil version of James Olsen, he refers to himself as “Superman’s Worst Pal.” This, of course, is the inverse of his moniker in the comics, Superman’s Pal Jimmy Olsen, which was also an ongoing series.

The Greater Arrowverse

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For fans of DC comic books and movies, many of the aforementioned Easter eggs probably didn’t go unnoticed. However, we’d be remiss if we didn’t touch upon those related to the Arrowverse itself.

Diggle vomiting after moving at super speed has become a running gag (no pun intended), and among the names on the Arkham Asylum doors is Guggenheim, M., which viewers may have guessed is a lighthearted jab at former Arrow showrunner Marc Guggenheim.

There’s also some clever breaking of the fourth wall, such as when Ralph says “it’s not even Tuesday” (The Flash took Supergirl’s Sunday night slot on The CW’s lineup and vice versa) and when Barry says “this has gotta be the craziest thing you've heard in the past three hours” in Part Three (aka hour three) of the crossover.

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It’s also worth noting that Part One introduces the longtime Justice League villain Amazo, who escapes from Ivo Labs… except we’ve already seen Amazo and Ivo in the Arrowverse. In Season 2 of Arrow, Dr. Anthony Ivo (the creator of Amazo in the comics) took his ship (which was also named Amazo) to Lian Yu to hunt down the powerful Mirakuru serum. Coincidentally, it’s a nano-adaptive hybrid of Mirakuru that gives this new Amazo its ability to steal metahuman powers.

Last but not least, there’s the long-running fan theory that John Diggle is actually John Stewart of the Green Lantern Corps. While it’s nothing more than a fan theory (at least as far as we know), the writers still give it a shout-out when the Earth-90 Flash sees Diggle and asks him where his ring is.

Could this be a sign of things to come? Probably not, but with Crisis on Infinite Earths coming to the Arrowverse next year, it stands to reason that nothing is completely off the table.

The Flash returns from its winter hiatus on Tuesday, January 15, with Supergirl coming back on Sunday, January 20 and Arrow on Monday, January 21.