Superman is one of the most popular and iconic superheroes in the world. With nearly 90 years of history, the Man of Steel has seen and done just about everything, capturing the imaginations of readers for generations and even leaping off the pages of comics to become a cultural icon thanks to various adaptations. Superman is so well-known that you don’t even have to have read comics to know who the character is and some key facts about him. He’s just that popular.

However, while there are things about Superman that just about everyone knows, there are some facts and trivia that would surprise even die-hard comics fans. These are the facts that are a bit less known and, admittedly, sometimes on the weird side, or facts that go just a little deeper than basic knowledge. Here are seven facts about Superman that you won’t believe are actually true — but they are.

7) He’s Vulnerable to More Than Kryptonite

Kryptonite may be Superman’s best-known weakness and is often treated like it’s the one thing that can stop him, but the truth is, Superman has quite a few vulnerabilities. While Kryptonite (specifically green Kryptonite) can cause Superman some serious issues and even kill him, there are other ways to take down the Man of Steel. One of the most obvious is the sun. With his powers derived from his exposure to the light of Earth’s yellow sun, if you take that away he loses his superpowers and becomes vulnerable to attack and injury.

Beyond the color of the sun, however, Superman has some other key vulnerabilities. Magic is often cited as a weakness, which puts him at a disadvantage when going against magic-wielding foes or many supernatural creatures. One could also argue that Superman is vulnerable to mind control as it’s something we’ve seen happen in comics numerous times over the many decades. And, of course, there are the impacts of the other colors of Kryptonite to consider as well. Turns out, the Man of Steel definitely has his weaknesses.

6) Kryptonite Didn’t Originate in the Comics

Speaking of Kryptonite, while it may be Superman’s best-known weakness, its one that didn’t get its start on the pages of comics. We don’t often think about early adaptations of Superman, but given the character’s popularity, Superman was adapted as a radio show back in the 1940s. The long-running radio serial The Adventures of Superman debuted in 1940 and ran until 1951 for an astounding 2088 episodes and we have it to thank for Kryptonite.

In 1943, Bud Collyer, the actor who voiced Superman, needed some time off so they came up with the fictional mineral Kryptonite in the story “The Meteor From Krypton”. The story saw Clark Kent grow weak following his exposure to the mineral remains of his native Krypton and it not only gave Collyer the break he was seeking but also introduced what might be one of the now most iconic aspects of Superman lore ever.

5) He’s Immune to Vampires

While Superman may be vulnerable to magic, he’s actual a vulnerability for a very specific group of supernatural creature: vampires. In Superman #180 from 2002, Dracula attempts to turn Superman and the vampire pulls out all the stops in his efforts. However, he’s not able to seal the deal and when he bites Superman (which, let’s be honest for a second, we’re still not fully sure how he was able to bite Superman anyway but just go with it), Dracula bursts into flames.

As it turns out, because Superman is solar powered and a vampire’s primary weakness is the sun, biting Superman would give the vampire basically a big mouthful of sunlight in a sense. So, I guess we can add “vampire repellant” to the list of superpowers the Man of Steel gets from Earth’s yellow sun.

4) Clark Kent Canonically Exists in the Marvel Universe

Yes, Marvel and DC have crossed over several times over the years, bringing DC characters into the Marvel Universe and vice versa, but that’s not what we’re talking about here. Clark Kent actually canonically exists on Earth-616 in the Marvel Universe and has since X-Men #98 from the mid-‘70s. The product of something of a joke between creators Chris Claremont, Dave Cockrum, and John Byrne, Clark appears as a mild-mannered reporter for a major metropolitan newspaper. He also has a colleague and close female friend named Lois.

Clark Kent in the Marvel Universe gets a little bit better than just the clever reference to the character, too. Not only does Marvel’s Clark Kent very much look like DC’s, but there’s also a great moment in his first appearance where Clark bumps into Thor — who happens to be in disguise by wearing a pair of glasses not unlike the disguise Clark uses in DC.

3) He Couldn’t Always Fly

Being able to fly is one of Superman’s main powers so it might come as a surprise to know that it’s not a power that he’s always had. In fact, flight is a power Superman originally did not have at all. When Superman first debuted, the best he could do was jump really powerfully — it’s kind of where the “able to leap tall buildings in a single bound” comes from — but by 1941, they added flight to his abilities, citing his continued time on Earth as the source of this new power.

What’s particularly interesting about Superman’s flight powers, however, is that much like his Kryptonite weakness originating in a radio serial, Superman’s ability to fly also comes from adaptations outside of printed comics. Turns out we have those early adaptations to thank for quite a few iconic Superman things.

One of the interesting things about comic book superheroes is that they don’t always have some of the mundane details of everyday life to contend with — when’s the last time you saw a superhero balance their checkbook, for example? However, when real life details make their way onto the pages of comics, it makes for great trivia and that’s the case for Clark Kent’s Social Security Number. Established in the responses to fan letters in Action Comics in 1966, Clark Kent does indeed have a Social Security Number (Superman doesn’t, but then again, that makes sense because no one knows Clark Kent is Superman).

However, what’s interesting is that the Social Security Number assigned to Clark Kent in comics — 092-09-6616 — is actually real. It just didn’t belong to Clark Kent. That number belonged to a man named Giobatta Baiocchi who died a year before the number was given to Clark in comics. It’s a fascinating piece of Superman trivia.

1) Superman (Sort Of) Made a Sex Tape

This one might be the wildest Superman fact of them all, but Superman once almost made a sex tape with another superhero. In Action Comics #593 from 1987, Superman and Big Barda were both manipulated into making some, ahem, adult entertainment together when Sleez comes to Earth after being cast out of Apokalips for being too much of a weirdo. He ends up kidnapping both Barda and Superman and manipulating them into making some adult entertainment.

Fortunately for everyone involved, Superman is largely able to resist because of his strong morals which gives Mister Miracle time to show up and stop things. It looks like all Superman and Barda end up doing is a little smooching, but it’s easily one of the weirdest and wildest moments in Action Comics, a strange bit of Superman trivia, and just an absolutely insane story.

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