Tonight was the most Easter egg-heavy episode of The Flash to date.
Let's get right into it becuase this will take a while.
So...what did we see? What did we miss?
Read on, and comment below.
Fans might remember Henry Hewitt as Tokamak, the villain in the episode "The Fury of Firestorm." On Earth-1, he's a scientist -- but a cocky one with a chip on his shoulder who turned bad once exposed to the power of the Firestorm Matrix.
In the comics, Hewitt was the head of a corrupt energy conglomerate who tried to play hardball with Congress to manipulate markets on his behalf.
Tokamak's most notable accomplishment was probably the creation of Firehawk, a superheroine with powers similar to Firestorm's who was created when Hewitt kidnapped a Senator's daughter and subjected her to an experiment designed to recreate the accident that birthed Firestorm. He later attempted the process on himself, which is what gave him powers.
The character has made only sporadic appearances, most recently during the Dwayne McDuffie run on Firestorm in 2007. The New 52 villain Dataxen has been compared to Tokamak, but their only real commonality is having energy-based powers and operating in armor.
Some fans expressed disappointment when Barry Allen appeared on Earth-1 back in his earliest appearance on Arrow and wasn't wearing a bow tie.
The character -- DC's first Silver Age hero -- has almost always been drawn wearing one in his civilian life.
It became so much a part of his iconography that in Geoff Johns and Ethan Van Sciver's The Flash: Rebirth, a good chunk of pages was dedicated to giving the tie a backstory.
In that same shot, The Flash confirmed that Channel 52 is the news channel on Earth-2 as well as Earth-1. It's one of the most frequent Easter eggs on the show, so that's probably not surprising. There's likely one for each of the 52 earths...
...or are they infinite now? You can never tell.
Still on that same shot!
News 52 revealed that there's a Mayor Snart on Earth-2.
No word on which member of the Snart family went into politics on Earth-2, but it's likely Leonard.
After all, in the world of Flashpoint he did star in the Citizen Cold miniseries.
That sure doesn't look like Oliver Queen, does it?
There's another Green Arrow we know is coming to DC's Legends of Tomorrow soon, though.
Could this be our first look at Connor Hawke?
Yes, folks, that was Melissa Benoist as Supergirl that you just saw on The Flash.
And, since Barry Allen was moving through a breach in the multiverse, it's likely safe to assume that she comes from a different Earth.
While many fans assumed that Supergirl and The Flash take place on different Earths because the title of their March 28 crossover episode is "Worlds Finest," without the apostrophe, seeing her out there in the multiverse alongside an alternate Green Arrow and the John Wesley Shipp version of The Flash feels like hard confirmation.
The idea that Supergirl exists on a different earth is a mixed bag for fans. It means that the character is unlikely to team up with the grounded and gritty Arrow or the time-traveling DC's Legends of Tomorrow. Legends EP Phil Klemmer recently told reporters that the multiverse was The Flash's thing, and their time traveling will remain on Earth-1 for the foreseeable future.
It also explains why the general public is so reluctant to accept The Flash and other super-powered heroes. In the world of Supergirl, her cousin has been Superman for years and is a beloved public figure. Many fans have pointed out during the run-up to finalizing a crossover that it could create continuity hiccups in the Arrowverse to have them share a world.
Of course, that isn't to say there's no Kryptonians on Earth-1. Remember, Rip Hunter on DC's Legends of Tomorrow last week told the team that he has "seen Men of Steel die and Dark Knights fall."
LONG LIVE THE LEGION
As Barry made his way through the breach to Earth-2 on tonight's episode of The Flash, we got glimpses of a lot of cool, alternate-universe characters from around DC's multiverse.
Earlier this month, Supergirl and The Flash EP and DC Chief Creative Officer Geoff Johns hinted that the Legion of Super-Heroes appearing on one of the TV shows he oversees.
A lot of fans assumed that would be DC's Legends of Tomorrow, which launched last week and which boasts time travel as a staple of the show -- but then there were comments that the show wouldn't travel past 2166.
While technically the Legion could come back from the future to 2166 or earlier, the reality is almost any version of the 31st Century the Legion might come from, would make Vandal Savage not all of history's worst threat, as he's so far been characterized, but a bump in the historical road.
I speculated that the odds-on favorite was likely Supergirl, given her past association with the team, but now it appears he was talking about this shot.
JOHN WESLEY SHIPP AS THE FLASH
On tonight's episode of The Flash, as the team popped through the breach between Earth-1 and Earth-2, a number of DC's multiverse characters...including Melissa Benoist as Supergirl and, yes, John Wesley Shipp as TV's original Flash.
Also in that tunnel: What appears to be the first appearance of The CW's Jonah Hex, who will soon appear on DC's Legends of Tomorrow.
The CW's take on Hex is described as "A true legend of the Old West, a morally ambiguous gunslinger with a penchant for danger. Surprisingly, he knows a thing or two about time travel and the future, but is at home in the Wild West. He’s been battling outlaws and gangs for awhile now, and advises the team to be extra careful when they arrive in the small town of Salvation."
Salvation, for those who don't follow the adventures of Jonah Hex, was the name of a Texas town where Jonah became caught up in a battle between a fundamentalist Christian named Sister Agatha who ran the town with an iron fist, and a group of local Apaches.
"Ever since we decided that Legends would involve time travel, we were eager to do a story set in the Old West," said executive producer Marc Guggenheim when Hex was announced. "But if you’re going to do a story set in the DC Universe version of the Old West, you simply MUST include Jonah Hex in it. We’re thrilled about bringing another well known, beloved DC character to television."
Hex, currently listed as a guest star with an option to recur, will make his first appearance in the eleventh episode of the show's first season.
Longtime DC Comics fans will remember that Jonah Hex is no stranger to time travel; despite spending most of his existence as a Man With No Name-style drifter and bounty hunter, at one point the character starred in a series simply titled Hex, in which he was kidnapped by a villain who transported him to a post-apocalyptic, 21st Century Seattle, where Hex operated for a while before being returned to his proper time. He also took place in the Crisis on Infinite Earths.
More recently, he's interacted with present-day DC heroes and locales both in Blackest Night -- Jonah came back as a Black Lantern -- and in All-Star Western, where he encountered Booster Gold and ended up thrown into modern-day Gotham City before Booster could find him again and return him to his past.
Booster, of course, is the father of DC's Legends of Tomorrow Time Master Rip Hunter; Booster and Rip also encountered Jonah during one of their early adventures as partners about ten years ago, when they enlisted his help to prevent the murder of a man whose descendants would one day prove essential to Superman's survival.
Hex has appeared in a number of animated series, but is likely best known to casual fans as the title character of a much-maligned 2010 live-action movie in which the character was portrayed by Avengers: Infinity War villain Josh Brolin.
We also get a look at Grodd, last seen in "Gorilla Warfare" when Harrison Wells and Barry exiled him to Earth-2's Gorilla City.
"A free and just society."
That's the motto of the Central City Police Department on Earth-2...
...home to the Justice Society of America in the comics.
While it might just seem like a clever misdirect to have Iris be a detective so that when the news says "Detective West," the Earth-1 crew can be confused, it's worth nothing that back in the pilot to The Flash, they referenced the fact that Iris had wanted to go to the police academy, but Earth-1 Joe stopped her because it was too dangerous.
On Earth-1, Floyd Lawton is an outlaw who uses his perfect marksmanship to commit murders for hire and eventually dies while serving in A.R.G.U.S.'s Suicide Squad.
On Earth-2, Lawton is a cop in Central City, known and widely mocked for his terrible aim and, from what we saw tonight, generally poor firearm handling.
On another Earth, it plays out more or less the same way as Earth-1, except he probably doesn't die because he's being played by Will Smith.
On Earth-2, we're seeing a lot of polar opposites -- Deadshot is a good guy who can't shoot and police captain Singh is a crook being carted through the police lobby in chains.
During 2010's Blackest Night event, the then-dead Ronnie Raymond came "back to life" as a member of the Black Lantern Corps and waged war on humankind alongside his fellow Black Lanterns.
Interestingly for this conversation, Firestorm's flames presented themselves as being blue/black as Deathstorm.
Upon encountering the new Firestorm, Jason Rusch, Black Lantern Ronnie attacked his girlfriend. Jason tried to pull Black Lantern Firestorm away from her, only to end up fusing with him. Ronnie, who didn't have the scientific knowledge required to use Firestorm's transmutation powers without help, used Jason's captive mind to turn the Deathstorm form into a deadly, evil version of Firestorm's worst self.
Later, Deathstorm would separate himself from both Ronnie and Jason and come back as the first Black Lantern to rise on his own, without his former "self." He would recur as a threat for a long while. He explains later that he's kind of death personified, filtered through the Firestorm matrix.
In the post-Flashpoint universe, Professor Stein was Deathstorm. Born on Earth-3, he was contracted to battle the Crime Syndicate, a brutal, alternate-Earth version of the Justice League, but instead experimented on himself, transforming himself into the being.
She'll be back next week, too!
Caitlin Snow is finally Killer Frost -- an evolution that took the better part of two seasons and still isn't "really" an evolution since it's only on Earth-2.
In any event, this is Caitlin's comic book destiny -- a villain who sucks the heat out of her unsuspecting victims. Pairing with a heat-and-energy-producing character like Firestorm is a dream come true because she can touch somebody without killing them.
Now that that's been taken away from her, it's a safe bet she won't be eager to work with Zoom again...!
TICKETS TO ATLANTIS
During her call with Barry, Nora Allen thanks her son for the tickets to Atlantis that he arranged.
Not only is Atlantis the home of Aquaman, but this is the second time it's been referenced as a place Earth-2 people can go. One of Jay Garrick's best friends is from there, after all.
Besides revealing that Eddie Thawne is still alive, and apparently a friend of Barry and Iris's on this Earth...
...look at those other names.
Yeah, the showrunners confirmed for us that it was "just Easter eggs," but still: Bruce Wayne, Hal Jordan and Diana Prince are on Barry Allen's speed dial.
Apparently Jitters isn't a coffee place on Earth-2, but "Jitterbugs," a jazz club.
Well played, Earth-2. Well played.
JOE CAN SING
Of course, in real life, actor Jesse L. Martin is a pretty well-regarded singer, with one of his best-known roles being in Rent.
So when it came time to give him a non-police job on Earth-2, why not jazz singer? It works!
Back on Earth-1, we get our first look at Geomancer.
Actor Adam Stafford plays Adam Fells, also known as the DC Comics villain Geomancer -- a foe of the Justice Society's, co-created by DC Chief Creative Officer and The Flash executive producer Geoff Johns.
Adam Fells was a big fish in a small pond until he joined up with the Injustice Society and bad things started to befall him, building to his death. A successor came along, taking up the name and costume, but didn't make many appearances before the New 52 reboot.
In the TV series, Geomancer is described as "a dangerous meta-human with the unique ability to create earthquakes. Intent on destroying the Flash, Geomancer uses his powers to unleash a string of targeted earthquakes, optimistic that he’ll draw out the Flash for a mano-a-mano fight to see who’s the most powerful metahuman in Central City."
PASKO & 4TH
So one of the streets in Central City is named for Martin Pasko, longtime DC Comics writer and editor.
During the Arrow/The Flash crossover, we saw Velocity 6, a speed formula developed by Harrison Wells.
Here, we get Velocity 7...which is edging closer to Velocity 9, a formula from the comics that can give speedsters increased speed for longer periods of time...but takes a toll on their body when it does.
In the comics, Reverb was Vibe's brother, who joined a for-profit superhero team known as The Conglomerate following the death of Vibe and hoped to be a hero to bring honor to his brother's name.
And, yes, that leather jacket has a design very reminiscent of the post-Flashpoint Vibe.