Hidden Batman movie details and Easter eggs

As different as they may seem, every Batman has a hidden symbiotic relationship with every other Batman out there, whether he's a flesh and blood hero or the original ink and paper vigilante. If you look close enough, you'll find secret connections between all of the Batmen you've ever seen, from campy to creepy. Here are 20 Easter eggs that connect all of the Batman worlds together into one weird Bat-universe.

Batman (1943) - The Bat's Cave

It's one of those aspects of Batman lore that's so well-known we just assume it's been there since the character's inception in 1939, but the Dark Knight's iconic cave didn't even exist until the 1943 Batman movie serial. Actor Lewis Wilson played the floppy-eared hero as a secret government agent in a bat-like suit, fighting World War II threats and radio-controlled zombies. For the first time, part of Batman's arsenal was his new secret underground lair, called "The Bat's Cave," which was so cool and appropriate that it became a permanent part of the comics. Also appearing here for the first time is a skinny Alfred, who had always been a bit plump in his comic appearances. The comic quickly followed suit, and the butler lost the butt.

Batman (1966) - Bright Red Batman

Adam West's goofy Batman was originally set to appear in a feature-length film prior to making his television debut, but 20th Century Fox was unwilling to finance an unknown property without at least testing it out. As a result, the psychedelic 1966 Batman TV series was pushed out first, and the film came out between the first and second seasons of the show.

When the film finally arrived in theaters, it was accompanied by a strange poster. While it's hard to mistake Batman for any other character, the poster's hero was bright red and black, instead of West's usual blue and grey. While these hues could be attributed to someone at the printer being a few bourbons into a long night at the press, it's actually a tribute to Bob Kane's original Batman designs, which used a red color scheme. Ultimately, it's not wholly inappropriate for the surreal 1966 Batman aesthetic—and it's pretty darn eye-catching to boot.

Batman (1989) - The Mark of Kane

Bill Finger and Bob Kane co-created Batman… or at least that's the polite thing to say. The truth is that the creation of Batman is a hotly contested issue, and the facts are buried back in 1939. The common story is that Bill Finger wrote and created a vast majority of the original Batman's world, and Bob Kane came up with some early, unused sketches before incorporating Finger's iconic ideas into the Batman we know today. According to legend, and Comics Alliance, Kane then apparently re-negotiated his contract so that he'd get complete credit and residuals for Batman—even on stuff he didn't actually work on.

But that's neither here nor there. An original Bob Kane drawing shows up during the course of Tim Burton's Batman: a joke drawing of a bat in a fancy suit handed to Alexander Knox, played by Robert Wuhl. Bob Kane was originally scheduled to make an appearance, but he was ill during filming, so only his drawing showed up in a cameo. It's a great homage to Batman's real world origins, no matter what you think of Kane, but it goes a little deeper. When the drawing is handed to Knox, Knox compares the sarcastic artist to an anatomical organ. Whether or not this is just a dumb joke or Tim Burton's comment on Bob Kane's notorious history is a Batman mystery that remains stuck under Burton's tangle of hair.

Batman (1989) - You Don't Know Jack

The Joker is probably the most mysterious comic character we have today. While writers usually delight in dissecting the origins and motivations of every possible hero and villain, The Joker simply doesn't have a real name or concrete origin story. Sure, some names have been suggested, but none are definitive. We accept that he was probably a small-time criminal who used to wear a red dome over his head, and that he fell into some chemicals that broke his brain and bleached his skin… but we still don't truly know who he was before that. And that's great.

So, the use of 'Jack Napier' in Burton's Batman is an invention only for the film, and it's a kind of Riddler-worthy double reference. It pays respect to Alan Napier, who played Alfred in the 1966 Batman TV show, and it's also a play on the word 'jackanape,' which means mischief. (It's also a specific type of tamed monkey, but nobody tell the Joker.)

Batman Returns (1992) - Pee Wee Redux

It's a cameo that you could easily miss, but Tim Burton film alumni Paul Reubens, who you may know as Pee-Wee Herman, makes a brief appearance at the beginning of Batman Returns as The Penguin's father. We never see him again after he tosses his horrible animal child into an ice cold river. Or do we?

Flash forward to Gotham, the 2014 TV series that explores the early life of a young Bruce Wayne and a bunch of other Batman-related characters, including Oswald Cobblepot. Here, Cobblepot is still in his early Penguin days, slim and devious, working his way up through Gotham's criminal underworld. In this incarnation, he's a doting son to his delusional mother, and it isn't until the second season that we meet Oswald's missing father…who is again played by Paul Reubens. Sure, his character is completely different this time around, but at least he gets a speaking part, he doesn't throw a baby into a river, and he sticks around for at least a few episodes before he's poisoned by his conniving second wife.

Batman Returns (1992) - Cat's Eye

Michelle Pfeiffer's Catwoman made a memorable addition to Tim Burton's Batman rogue's gallery. While it was really no secret that awkward Selina Kyle would eventually transform into a cat-themed villain by the end of the film, presumably because being licked by cats after you fall out of a window gives you wacky powers and a craving for milk, Burton found a pretty clever way to display her feline future before the ultimate transformation.

Earlier in the film, Selina is working at her desk when she's approached by the gross Max Schreck. As she's noting inconsistencies in some paperwork, the shadows cast by her glasses pretty closely resemble the catlike shape of the mask she'd wear just a few scenes later. Add to this the fact that Shreck starts talking about curiosity killing cats moments before tossing her out a window, and it's obvious that the allusion is much more than just a coincidence.

Batman Forever (1995) - Nightwing

Watch out, everyone; we've now entered Schumacher territory.

After Dick Grayson helps Batman for the first time, Grayson peppers the reluctant Bruce Wayne with potential sidekick names, including "Bat Boy" and "Nightwing." Comic readers will note that not only is Nightwing a much cooler title than Robin, which is a girl's name, but it's also the alias adopted by Dick Grayson in the comics after he quit his Robin gig in 1984. Nightwing becomes a solo hero who protects Bludhaven, a decrepit old whaling town which might be even worse than Gotham.

The Nightwing name goes back even further, however. In 1963, Superman took a page out of Batman's costume guide and called himself Nightwing during his adventures in the bottle city of Kandor. Dick Grayson's use of the name is inspired by Superman's use of the name…which was inspired by Batman, in an endless, inescapable, Batman-shaped vortex.

Batman & Robin (1997) - Gossip Gerty

Even though Bob Kane was unable to make his previously scheduled cameo, his wife Elizabeth managed to appear in a few Batman films. During Batman & Robin, Elizabeth Sanders can be seen in Gotham Observatory, as George Clooney's Bruce Wayne is dedicating the improbable, completely unscientific, Schumacher-esque telescope. As Gossip Gerty, she's somehow qualified to attend serious scientific events and interrupt them by asking Bruce Wayne about his girlfriends. She's also the emcee at the later charity auction, and also appears in Batman Forever as the same questionable journalist.

But that's not all. Sanders also appears as a random Gothamite with a small speaking role in Batman Returns. Fans have speculated that this just might be Gerty before she joined one of Gotham's various rags…adding a weird bit of continuity between the Burton and Schumacher years.

Batman & Robin (1997) - Droogs

Joel Schumacher's Batman movies have been roundly criticized over the years, but whatever you might think of his work in the franchise, he's at least familiar with classic works of cinema. Case in point: at one point in Batman & Robin, you can see a random gang member dressed up as a droog from Stanley Kubrick's A Clockwork Orange. And it's not the only Clockwork Orange reference in the world of Batman. In the video game Batman: Arkham Origins, a brief part of the classical Clockwork score plays while you're beating up thugs as the deranged Joker…a tip of the hat to the good old ultra-violence.

Batman & Robin (1997) - Al Headroom

After goofy Barbara Wilson taps her way into the Batcave by entering a ridiculous three-letter password that Batman should be absolutely ashamed of, she meets her virtual uncle Alfred on a giant computer screen. Kids of the '80s already know this, but the glitchy, stuttering vision of the old man is based on Max Headroom, a cyberpunk computer character who'd had his own movie and TV show back before the internet was a thing. Headroom, played by Matt Frewer, had a signature glitchiness, only appeared on TV screens, and kinda sounded like a scratched-up CD. (If you were born in the last ten years, a CD is that silver disc your mom uses to play music on her stereo.) Frewer himself actually has a place in the Batman universe, playing Sid the Squid in a 1993 episode of the Animated Series, "The Man Who Killed Batman."

Batman & Robin (1997) - Heart of Ice

Speaking of Batman: The Animated Series, it also helped inspire Batman & Robin's best scene. Even though the show was created for kids, it incorporated some fairly mature and serious themes, and was so well-written that many elements eventually found their way into Batman's comics canon. The character of Harley Quinn, for example, started out as an animated villain before joining official DC Comics continuity—and the cartoon series also told the most compelling Mr. Freeze origin story ever written.

Even though the DC Animated Universe eventually turned Mr. Freeze into a sort of robot spider, he started out as a humble, broken-hearted scientist trying to save his wife. In the episode "Heart of Ice," we see a snowglobe with a spinning woman inside, representative of Freeze's wife, cryogenically frozen until a cure for her disease can be found. It's so powerful that Batman & Robin borrowed it to give Schumacher's absurd version of the villain, played by Arnold Schwarzenegger, a tiny little bit of believable humanity. It almost works—until the next time Schwarzenegger busts out another "Ice to see you"-style quip.

Batman Begins (2005) - Joke's On You

Batman is never really complete without his chief nemesis, the Joker. You can't build a Bat-universe around R'as al Ghul and the Scarecrow, and Christopher Nolan knew it. So at the end of Batman Begins, Nolan planted an incredibly obvious signal about his next villain: a Joker playing card. It's not even an Easter egg. It's just telling you what happens next in the most obvious way possible.

But what audiences didn't really notice at the time was that the evidence was recovered by someone named "J. Kerr." While some people attribute this to Nolan offering another nod to the character, other fan theories suggest that the Joker didn't just leave his calling card at the scene, but infiltrated the Gotham Police Department to deliver the evidence labeling it himself. Some theories even suggest that Heath Ledger's Joker was a disgruntled cop, exposed to too much Scarecrow toxin before losing his mind. Either way, it's a weird hint at a larger mystery…or maybe nothing at all.

Batman Begins (2005) - The Final Countdown

Just because Batman fights an immortal warrior dude and a living scarecrow, that doesn't mean that these guys are the only crooks in Gotham. The city's criminal underworld is already vast and weird by the time Bruce Wayne slips on the cowl, as evidenced in the two brief appearances of notable Batman villain Mr. Zsasz. Zsasz, a bald assassin, can be seen in Arkham, as well as during a courtroom scene with Jonathan Crane. While bald bad guys are a dime a dozen, Zsasz's trademark death tally tattoo can be spotted on his neck. And if that's not confirmation enough, the actor playing this mysterious thug, Tim Booth, also voices Zsasz in the tie-in video game.

Batman Begins (2005) - Flock of Bats

If you're so into Batman that you went out and purchased the Batman Begins soundtrack so you could pretend to watch the film even when you weren't, you've just treated yourself to another awesome Easter egg. Hans Zimmer's soundtrack titles don't correspond to anything that's actually happening on screen; instead, they're various scientific names for bats. If you check out first letters of the track names, you'll notice that the middle six spell out 'BATMAN.' And while this clever acronym doesn't change the course of Batman continuity forever, it's still a sweet treat for eagle-eyed Batman devotees.

The Dark Knight (2008) - Perfect Timing

Attribute the following to director Christopher Nolan's meticulous eye for detail. When Batman is in Hong Kong during The Dark Knight, he plants some time bombs set to go off in two minutes and twenty-two seconds… and they actually do, exactly when they're supposed to. Generally, directors are pretty flexible with how they treat timed events, as long as they can fit in all of the action, but Nolan literally runs his productions like clockwork.

The Dark Knight (2008) - Paging Cesar Romero

During the film's opening bank robbery, the Joker gives the audience the old switcheroo by wearing a creepy clown mask, blending in with his many thugs before disappearing into a swarm of school buses. It's not immediately obvious, but the mask is a pretty clear tribute to the very first appearance of the Joker on the 1966 TV show. In "The Joker is Wild," the villain is seem wearing a remarkably similar mask before being unmasked as another kind of clown.

A similar mask can again be seen in the 2014 animated feature Assault on Arkham, weirdly connecting all three disparate universes together. Again, this is only one instance of many, and it continues through the end of Nolan's trilogy.

The Dark Knight Rises (2012) - The Red Phone

If you look carefully in the background of the scene where John Blake meets Bruce Wayne for the first time, you'll see a set of shelves, and on those shelves are some pretty iconic props.

Fans of the Adam West series will immediately recognize the bright red Batphone, the Dynamic Duo's hotline to Commissioner Gordon. A little less obvious is the bronze Shakespeare bust, which 1966 Batman used to access the secret door to the Batcave. Of course, it would be silly to use such garish props today… but not to slip them into the background. Though we do miss that Batpole.

The Dark Knight Rises (2012) - Cover Clown

The novelization of The Dark Knight Rises mentions an appearance of the Joker, who has survived the previous film and is now safely stored away in Arkham. Unfortunately, due to Heath Ledger's untimely death, the script for the third film had to be tweaked a bit. Still, Nolan didn't want to completely forget about Ledger, and it was deemed a bit too ghoulish to slip him into the film posthumously like some kind of Fake Shemp, so Nolan did the next best thing.

Without obviously reminding the audience that Ledger was gone, the Joker's image was slipped onto a magazine cover, quietly placed on a table for future DVD-pausing nerds to find. While it's not explicitly obvious that it's to signify that The Joker is still alive somewhere, since mass murderers don't generally get classy cover story headshots, it's an acknowledgement that his impact is still felt.

And now for a couple that exist just outside of the Dark Knight's own films.

Man of Steel (2013) - Keep Calm

At one point during Man of Steel, the first film in the new DC Extended Universe, we actually see a very early reference to Batman. Bear in mind that until 2016, we didn't really know that this universe's Batman had been fighting crime in Gotham for decades, and until 2015, we didn't know the characters would cross paths on screen.

As Superman is crashing through buildings, we can just barely see a "Keep calm and call Batman" poster through the dust and rubble. It's been confirmed that this was added by the special effects team after filming, and it's a little weird because it uses the Tim Burton Batman symbol and not the official DCEU logo, but after seeing Batman v Superman, the presence of the poster actually makes sense. People have placed their trust in the hero for years.

I Am Legend (2007) - Batman vs. Superman

The film I Am Legend presents a vision of the future where the world has been decimated by a plague—and apparently, it's also a ridiculous fantasy world where Batman and Superman share some screen time. At one point, a huge movie banner can be seen on the side of a building, combining emblems from the two superheroes. Back in 2007, such a thing was so far-fetched that it could only happen in a world that had already ended.

Scheduled to be released in 2010, the fictional film was not only something that I Am Legend's director wanted to see happen, but it was also a reference to Legend screenwriter Akiva Goldsman, who had actually co-written an early treatment of a potential film starring Batman and Superman.