The Flash has been through a long list of writers and directors since first being announced for a 2018 release by Warner Bros., but it's fair to say Phil Lord and Chris Miller generated the most excitement.
The LEGO Movie and 21 Jump Street directors once wrote a treatment for the project, and were later eyed to potentially write and direct. However, it didn't work out, and they instead focused on Spider-Man: Into the Spider-Verse (which is widely hailed as one of the best superhero movies of all-time).
When Lord and Miller were working on The Flash, the movie was still set firmly in the same DC Extended Universe that Zack Snyder had created. That means it was going to tie into the events of Justice League, which is where Barry Allen was first expected to discover that he can travel through time. Kiersey Clemons was also set to play Iris West at that point.
Now, Lord has responded to a fan on Twitter to say, "We cooked up something really fun. Lovely spending time with Zack [Snyder] and team and seeing what they were up to."
Check out Lord's Tweet below:
Click on the "Next" button below to see some of the
alternate universes Barry Allen could visit in The Flash!
10. Green Lantern's Universe
Ryan Reynolds has denied that he's returning to the DC Universe for the Snyder Cut of Justice League, but if Warner Bros. can convince him to return for The Flash, that would be no bad thing.
Revisiting his version of Hal Jordan after more than a decade would be undeniably good fun, while we're sure Reynolds would enjoy poking fun at his time as this character. Who knows, the movie could even god some way in redeeming his Green Lantern, leaving the door open for a possible return.
A team-up between the Flash and Green Lantern is something fans have wanted to see on screen for years now, and The Flash movie could finally make that fantasy a quirky, enjoyable reality.
9. The Arrowverse
One of Crisis on Infinite Earths' most memorable moments came when the big screen version of Barry Allen met his television counterpart. It was at this point Ezra Miller's version of the character learned of the Multiverse's existence, so why not revisit that exchange at some point in this movie?
For fans of The CW TV series, this would be a rewarding moment, and a great way of potentially bidding farewell to Grant Gustin's version of the hero (he's only signed up for two more seasons).
We wouldn't expect this to be much for than just a cameo, but after what happened in that small screen crossover, it would be a real missed opportunity not to at least touch on the Arrowverse's importance. After all, it's actually been around longer than the DC Extended Universe at this point.
8. The DC Comics Universe
This would be a hard one to pull off, especially as the comic book DC Universe is constantly changing. However, just imagine a brief sequence which sees Barry Allen arrive there and find himself surrounded by familiar faces, albeit in comic accurate costumes (based on The New 52, perhaps).
That would be a neat moment, and visual effects could even be used to make this alternate reality look like a comic book brought to life, something we saw in Spider-Man: Into the Spider-Verse.
It would be best for The Flash to pinpoint one era in particular for this reality, but the source material deserves to be referenced in a meaningful way, and this could achieve that in a seamless manner.
7. Batman Forever/Batman And Robin's Universe
Val Kilmer is set to be part of DC FanDome this weekend, and while it's unlikely that he'll be there for The Flash, why shouldn't he return if Michael Keaton and Ben Affleck are getting to suit up again?
He may have only played the Dark Knight once in Batman Forever, but that movie has a devoted fan following, and this cameo is far more likely than George Clooney showing up (Batman and Robin remains something of a blemish on his career). This camp world is a real contrast to the one Keaton and Affleck's Bruce Waynes call home, so that alone makes it a must-see destination.
There's no reason for this not to happen, and these Batmen sharing the screen would be epic to see.
6. The Animated Universe
Whether we're talking about Batman: The Animated Series, Justice League Unlimited, or even the direct-to-DVD animated features which have become a staple in recent years, the DC Universe has a rich history in animated form. With that in mind, there's no reason not to touch on that here.
Would it be too goofy to have the Flash arrive in a world where he's suddenly, well, a cartoon?
Yes and no, but if the Fastest Man Alive is going to race through world after world, there's no reason one of his destinations couldn't be animated in the unique style of Bruce Timm. Some legendary voice actors could be enlisted, and some great stories will finally be acknowledged in a big way.
5. The Dark Knight Trilogy Universe
Earlier this summer, it was revealed that if Michael Keaton turned down the opportunity to return as Batman, Warner Bros. might consider turning to Christian Bale. That seems highly unlikely given his past comments about the possibility of reprising the role, but could the actor be talked into a cameo?
His story obviously came to an end in The Dark Knight Rises, but that doesn't mean the Flash couldn't pay a visit to his world and meet the new Batman (Joseph Gordon-Levitt's "Robin").
This would be an admittedly strange moment given the isolated nature of Christopher Nolan's The Dark Knight Trilogy, but it's hard to believe Warner Bros. would ignore such a huge part of the Caped Crusader's big screen history. Seeing Bale suit up again would obviously be a dream come true.
4. Superman's Universe
Sadly, Christopher Reeve is obviously long dead, but that doesn't mean his time as Superman couldn't be referenced in The Flash. Crisis on Infinite Earths beat this movie to the punch in some ways as we did head to a post-Superman Returns world to find Brandon Routh's older Man of Steel.
Heading back there could be a tad redundant, but Warner Bros. could choose to use visual effects in order to recreate Reeve's likeness and have Barry Allen see this alternate Superman from afar.
That and John Williams' iconic theme would stand out to longtime fans of the DC Universe, and The Flash revisiting such an iconic part of Warner Bros.' history in a movie like this is arguably a must.
3. Watchmen Universe
This is a tough one, as it's hard to imagine us heading back to 2008's Watchmen and even harder to believe the Flash would race into the world Damon Lindelof created with his stellar HBO series.
Still, with DC Comics making use of these characters, we're sure the Fastest Man Alive could briefly arrive in a desolate version of New York City and see a newspaper headline referencing a giant squid attack. This wouldn't be much more than an Easter Egg, but those of us who are fans would get it!
It might be a little too soon for a big screen DC/Watchmen crossover, but The Flash could certainly tease it.
2. Flashpoint Universe
Recently, it's become clear that we're not getting a straightforward Flashpoint adaptation. That more than likely means much of the comic book story's bigger moments won't make it into the movie, and it was recently reported that there will be no war between Atlantis and Themyscira.
That's a shame, but it doesn't meant The Flash can't pay homage to it in some way. As Barry Allen races through the Multiverse, he could quite easily find himself in a world where Aquaman and Wonder Woman are battling each other. This would help him realise just how different his friends could end up being in the new world he creates, and could make for an epic action set piece.
Cameos from Jason Momoa and Gal Gadot are also more likely than full-blown leading roles.
1. A New DC Extended Universe
By the time all is said and done in The Flash, we're confident that a new DC Extended Universe will have been created. There are already hints that Michael Keaton's Caped Crusader will be that world's new Batman, and this makes sense if you're remotely familiar with the comic books.
Just how drastically Warner Bros. intends on rebooting this world remains to be seen, but it's likely that the "SnyderVerse" will become its own separate thing in order to simplify continuity.
Bear in mind that director Andy Muschietti has said everything we've seen before now has happened, so it doesn't seem like a stretch to assume his movie will wipe away a lot of stories, only for us to learn that they took place in separate worlds. The question is, will the new DCEU rival the MCU?