Today, after literally years of teasing fans in interviews and on social media, Dwayne Johnson revealed that he'll be playing Black Adam in Warner Bros.' upcoming 'Shazam' movie. This is interesting news for a variety of reasons, but let's stick to two. First, it means that Johnson will be playing the villain of the film, not the titular hero. Second, it means that the role of Shazam himself is wide open and it's a role that needs to be cast with great care and responsibility.

Although Shazam may not a household name like Superman or Batman, he's one of the most powerful superheroes in the DC universe. Created in 1939 and brought into the DC family in 1972, Shazam has gone through many changes over the years (including a name change from Captain Marvel) but the basic conceit of his character remains the same. When young Billy Batson says the magic word "Shazam!", he transformers in a powerful superhero with the abilities of six godlike figures: Solomon, Hercules, Atlas, Zeus, Achilles and Mercury. Yes, you should be paying attention to the first letter in each of those names.

Shazam is the superhero equivalent of 'Big.' He may look like a musclebound superhuman who can throw lightning bolts and stand toe-to-toe with Superman in a fight to the death, but he's literally a kid in an adult's body. This means he can be helplessly naive, but it also means that he's innocent and pure, free of the baggage that corrupts his fellow adults. While most superheroes look at their business of saving the world as a core and a job, it's fun for Billy/Shazam. At its heart, this character is all about wish fulfillment. It allows young comic book readers to see one of their own become a superhero. They can live vicariously through this figure as he saves the world as a superhero despite being an 11-year old boy.

Let's get this out of way: it's a shame that Dwayne Johnson chose to play Black Adam instead of Shazam. But it makes sense: on paper, he's a more complicated and compelling character, a former supervillain struggling with his identity and transforming into an antihero with murky motivations. There's no doubt that Johnson will rock (pun intended) this part and give it all of the necessary gravitas and menace. However, Johnson, for all of his muscles and glowering, has something that many men of his stature lack: the capacity to play innocence. He can play an action hero, but he can also play a big goofball. He's self-effacing and funny and entirely unafraid to look silly. He'd be perfect to play a young kid inside the body of a juggernaut.

But Johnson made his decision and it's time to move on. The question now is which actor can play Shazam? Who has those necessary qualities? Who has the physicality to play a man who can destroy a mountain with a punch and look utterly joyful at his ability to to that in the first place?

Those are purely rhetorical questions at this juncture, but Warner Bros. should actually take a page from from the Marvel Studios handbook on this one and cast someone best known for being funny before they pursue an actual action star. In the wrong hands, this character could be just another glowering strong guy in a cape. Give it to someone with the charm and range of, oh, Chris Pratt and Robert Downey Jr., and you've got something special.

Because we've seen what happens when you strip Shazam of any joy. When the DC comics universe rebooted a few years back with their "New 52," Shazam was recreated in a way that still has fans up in arms. Young Billy Batson was no longer a wide-eyed kid with good intentions, but a scheming delinquent who makes the lives the people around him a living hell. This meant that his Shazam was not a noble and slightly silly superhero, but a grim-dark vigilante with a bad attitude. Considering that rumored "no jokes allowed" policy going on at Warner Bros. regarding their superhero movies, this is the worst case scenario. A 'Shazam' movie with no sense of fun is no fun at all. This is a Boy's Own Adventure. To pretend it's something else is to lie to yourself.

Put on your fan-casting hat for a moment. Imagine a 'Shazam' movie where the sinister threat portrayed by Dwayne Johnson is fought by a colorful, blissfully innocent superhero played by, oh, let's say Channing Tatum. He's got the physique to fill out that red suit, but he's proven his comic chops time and time again. No leading men are as unafraid to get silly as Tatum. How about going even further outside the box and look at comics like Rob Riggle? With the right training, he could transform his massive frame into a truly superheroic build and it's easy to imagine him embodying a kid in an adult's body. Plus, there's the fact that he's the spitting image of the comic book character.

Fearing the worst for a movie that doesn't even have a finished script yet is beyond silly, but Warner Bros. is making it easy to be cautious for 'Shazam.' This film cannot be as serious as 'Man of Steel' or 'The Dark Knight.' Its lead cannot be Just Another Guy With Abs. This is their chance to make adventurous and fun and just silly enough. If done right, this is the kind of movie that every 8-12 year boy in the world will fall in love with.

Hopefully, that No Jokes rumor won't apply to a DC comics character who offers more opportunities for humor than anyone else. Hopefully, the New 52 version of the character is not what everyone is looking at when they make this movie. Hopefully, the cinematic Shazam will be played by an actor who understands what a tricky balancing act Billy Batson really is.