As you all know, Clark Kent is originally from the planet Krypton, which had a different atmosphere than Earth. Our planet's yellow sun and its radiation is what give Superman his incredible powers. Chief among them is his near invulnerability: the only thing that can truly harm him in a meaningful way is Kryptonite (and magic in the comics).

But Kal-El actor Henry Cavill says there is something else that can defeat him: his own mind.

"The only thing that can really beat Superman is Superman," Cavill said in an interview with The Guardian.

Don't take Cavill's words on the nose; Superman isn't going to punch himself in the head. Instead, think of his statement as an extension of Superman's psyche.

The last son of Krypton is the most powerful being on Earth (though there are some demigods and metahumans that can pack a whollop as well). On top of that, he's a moral man who wants to use his powers to help the world. Thus, he is always second-guessing his decisions and debating which course of action is the right one. That's a lot of responsibility to thrust upon one's self.

We saw the seed of this idea planted at the end of Zack Snyder's 2013 film "Man of Steel" when Superman is forced to kill General Zod in order to save innocent lives. The action takes an emotional toll on Superman's character, and fans will see the guilt he struggles with in next year's "Batman V Superman: Dawn of Justice."

As a result, he may place self-imposed limitations on himself when fighting Batman, Lex Luthor or even Doomsday during his next appearance. In essence, the only thing that can weaken him is his own resolve. Although "Man of Steel" had its flaws, that is a very interesting concept to touch upon. Those of you that are rooting for DC's Extended Universe should look forward to seeing that idea further explored in "Dawn of Justice."