[WARNING: This article contains SPOILERS for The Flash Season 2, Episode 13.]

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By now, everyone even causally interested in the growing slate of comic book television shows knows that over at Marvel, the TV shows are set in the same Marvel universe in which the blockbuster Avengers universe takes place. Whereas over at DC Comics, the TV shows and Justice League/Suicide Squad universe are completely separate (for now, anyway). To complicate matters even further, the fact that the DC TV shows are spread across multiple networks led many to believe that a single shared universe was impossible. In other words, ArrowThe Flash and their shared universe Legends compatriots would have to suffice.

While we maintained that a single shared universe could be more possible than fans would think (since nearly all DC shows are being handled by the same people), the past few weeks have done the work for us. First, a crossover between The CW's The Flash and CBS' Supergirl was officially announced. But the producers saved their biggest surprise for The Flash's trip to Earth-2, when the trip offered a glimpse of the full DC Comics Multiverse - revealing how Supergirl connects to the show's world, a previous superhero show is also linked, and hints at even more characters coming to The CW and beyond.

We'll break down the standout visions, and why the showrunners may have just confirmed that not just the main DC Comics TV show, but any DC Comics TV show is taking place alongside the others... from a certain perspective.

Jonah Hex & Gorilla Grodd

The Flash Earth-2 Jonah Hex Grodd

First off, some of the visions are easier to classify, given recent developments in The CW's other superhero programming. A random gunslinger doesn't mean much on his own, but it seems this is the very first official look at the network's version of Jonah Hex (played by Johnathon Schaech). The legendary DC Comics cowboy will be coming to Legends of Tomorrow when the cast take a trip back to the Old West, and meet Hex who, according to this photo, has a much less grisly version of the facial scarring he's known for in the comics.

Following shortly after is none other than Gorilla Grodd, the former Flash villain who was dealt with earlier in Season 2 of the show. The last fans saw, Grodd had been shuffled away to Earth-2, deep in the jungles of Africa outside of what looked to be Gorilla City. The producers have confirmed that Grodd and Gorilla City are a long term storyline, but definitely more than a throwaway easter egg. Perhaps his appearance here is meant to reassure fans that he truly does have a future in The CW's superhero universe. Fingers crossed.

The Supergirl Connection Explained

The Flash Supergirl Easter Egg Universe

From the moment the first rumors claimed that a crossover adventure was being planned between The Flash and Supergirl, the naysayers made their objections known. How, they asked, could a flying, superhuman alien have existed alongside Central and Starling City this entire time, without any character ever mentioning it? It was a fair point (although fans eager to see Grant Gustin and Melissa Benoist share the screen would probably have suspended their disbelief). Thankfully, the actual solution seems to have been offered.

Supergirl doesn't exist in the same universe as The Flash and Arrow, but on a parallel Earth, in the sprawling DC Multiverse. With Barry and the S.T.A.R. Labs team having already hopped from their own Earth to 'Earth-2,' it's just as possible that another breach could be opened between their world and any number of parallel ones. Apparently, one of those is going to lead straight to National City, the stomping grounds of the Girl of Steel. The real question, then, is whether there's a version of Barry Allen and Oliver Queen walking the streets of Supergirl without anyone knowing it...

CW Wants Supergirl Arrow Flash Crossover

It's a clever solution, and shows how DC boss Geoff Johns' claim that all DC properties exist in one Multiverse was more than just lip service. It may have been written off as an excuse for a lack of crossovers, but it seems Warner Bros. and DC Entertainment have at least some interest in mixing their properties. As this Supergirl appearance suggests, the shared-but-divided Multiverse may be their way of pulling it off, while keeping each story operating on its own terms (playing the same role as it did in the comics).

Next: Glimpses of Arrow, The Flash &... Booster Gold?

The Most Shocking Reveals/Teases To Come

The Flash Trickster 1990 TV Show

Finally, we get to the good stuff. As the image above shows, it isn't just current TV shows starring DC Comics superheroes that got their welcome into the Multiverse, but those of old. Specifically, the 1990 Flash TV show starring John Wesley Shipp as police scientist turned speedster Barry Allen. The showrunners of Arrow and The Flash have made their love for the original series known, not only casting Shipp as the father of Gustin's hero, but bringing back Amanda Pays to reprise her role as 'Dr. Tina McGee,' and Mark Hamill as the villainous 'Trickster.'

By including an image of Shipp from the CBS series here, fans have more than enough reason to infer the real message being sent: that The Flash (1990) exists in the current DC Multiverse, on a parallel world to that of The CW's shows. Could it be a world in which Henry Allen was given the same powers in place of his son? Were fans of the original TV show actually watching the heroic adventures of Henry Allen, while his alternate universe doppelganger was meeting his wife, Nora, and having the son who would carry the same mantle?

The questions are endless, and speak to the spirit, if not the letter of DC Entertainment's TV Multiverse. Given this evidence, can we assume other DC shows - Lois & ClarkBatmanSmallville - are fair game to be glimpsed in parallel worlds, whether or not characters actually choose to stop and stay a while?

The Flash TV Multiverse Explained

The difference is a subtle, but important one: some will claim that such a move is still dodging the issue, and that a "shared multiverse" isn't a "shared universe"... while others wonder if the distinction actually matters. But it's not the only image of a DC Comics hero that is sure to get fans talking. Given how quickly the green hood slipped past, and the recent announcement that Legends would feature an older, goatee-ed Oliver Queen, some may have assumed they were seeing a similar glimpse. But take a closer look, and that's certainly not Stephen Amell under the hood and domino mask.

Are we being shown an alternate world in which someone else ook up the identity of the Green Arrow? Or seeing a future, or one possible future, in which a man was forced to take up the job after Oliver Queen was unable to? These trips through time and space have been hard to define in the past, and if Jonah Hex's appearance is merely a sign of things to come, then perhaps this storyline has yet to be told... or yet to be prevented by Rip Hunter and his Legends.

Finally, that piece of jewelry may prove to be the biggest bombshell of the group. For those who know the meaning behind the 'L' symbol, it's more than just a ring. It's a ring which grants the wearer the ability to fly, an is given only to members of the Legion of Super-Heroes, the 31st Century superteam who looks to DC's Justice League heroes as their inspiration.

On its own, it's hard to know just what the producers are getting at. There were rumors of a Legion of Super-Heroes movie in development years ago, but when dealing with these particular producers, another character rises to the top of the list...

The Flash Legion Ring Booster Gold

That's right, Booster Gold. Aside from the fact that Andrew Kreisberg, The Flash's showrunner was originally developing a Booster Gold TV series before heading to The CW, Geoff Johns claimed that "chances were good" of seeing Booster pop up in one of The Flash's time travel stories. Since the future athlete-turned-wannabe-superhero gains his powers by pilfering a Legion Flight Ring from a museum before heading back in time, the ring in question could be the very same one. It's too early to tell, but this may be the very first look at a Booster Gold TV role in the making.

Especially when you consider that Booster is, you know, Rip Hunter's father.

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Those are our thoughts on these images spliced into The Flash's latest trip through time and space, but what do you make of them? Are you excited to see that all DC Comics properties are potentially being included in the Multiverse, or do you wish the shows were taking a different route? Any theories on what to make of Diggle or the Legion Flight Ring? Let us know in the comments, and we'll keep you posted as more information arrives.

Next: Every Earth-2 Easter Egg on The Flash Explained

Supergirl airs Mondays @8pm on CBS. The Flash airs Tuesdays @8pm on The CW. Arrow airs Wednesdays @8pm on The CW. DC's Legends of Tomorrow airs Thursdays @8pm on The CW. The Flash aired @8:30pm on CBS sixteen years ago.