It's a comic book world, we're just all living in it. Nowhere is that more evident than in the world of sports, where athletes and fans bring their love of comics right into the stadium with them.

Take Houston Astros pitcher Lance McCullers for example. The rookie made his big league debut Monday night against the Oakland A's and sported Batman cleats on the mound.

Of course Batman is only mortal, and so was McCullers. He pitched 4.2 innings in an Astros loss. But he isn't the only sports figure to carry the flag -- or cape, as the case may be -- for superheroes.

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The Dark Knight Rises

In a 2013 Sports Illustrated cover story, Tom Verducci referred to Harvey as "The Dark Knight of Gotham" and, needless, to say, the nickname stuck. Now you can get all kinds of Matt Harvery/Dark Knight merchandise. Even Harvey himself has taken to the name, going so far as to have "Dark Knight" carved into his bats.

NFL "Superheroes"

In February, the folks at the popular Facebook page "NFL Memes" took up the task of converting some of your favorite NFL stars into superheroes.

Obviously, they have Calvin Johnson as Megatron.

megatron -- cj
(NFL Memes)

Though, the best is probably a Papa John's-toting Iron (Peyton) Man(ning).

iron man - manning
(NFL Memes)

Check all of them out here.

Super Sergio Romo

Someone let me know where I can find Courageous Catcherman, first edition.

The Other Hulk

(Getty Images)

You've probably never heard of Givanildo Vieira de Sousa, but if you're a soccer fan you've probably heard of Hulk, a striker for Brazil's national team and Zenit St. Petersburg. Due to lengthy familial names in Portuguese-speaking countries, many players opt to put a nickname on their shirt over a family name. This is why one of the world's best soccer players gets to run around with the name of a superhero on his back.

And just in case you were wondering why his nickname is Hulk...

(Getty Images)

That's why.

Everyone Wants to Be Superman

It's a given that naming Superman as your favorite superhero is a huge cop out. (Oh, the dude who is an almost invincible goody-two-shoes is your favorite? Cool, cool.) However, that hasn't stopped many athletes from trying to take the moniker for themselves.

The original sports Superman was Shaq. Although, we're pretty sure he relinquished that title after playing a fellow DC Comics character in the terrible 1997 movie "Steel." Then Dwight Howard wanted to be Superman, which further fueled comparisons between him and Shaq. In football, Robert Griffin III wore Superman socks to his Heisman ceremony, while Cam Newton has become known for his Superman touchdown celebration.

How about we just stop all of this right now and place a moratorium on athletes nicknamed Superman? It is decided.

Cy Brown is a contributor to Sports on Earth. Follow him on Twitter @CEPBrown.