It's been over a decade since superhero movies started ruling the world. And everybody keeps expecting it to end any day — Matthew Vaughn said he did X-Men: First Class because he thought it might be his last chance to do a big superhero movie before the bubble burst. But instead, 2012 is the year of the superhero, with Avengers, Dark Knight and Spider-Man. Plus the sleeper hit Chronicle!

So how can you tell when the superhero movie boom is finally over? Here are 20 sure signs to look out for.

The thing about superhero movies is, there are only really a handful of viable properties for a $150 million-plus movie. There are the A-listers like Superman, Batman, Spider-Man, Fantastic Four, the Avengers and the X-Men (including Wolverine). And then a handful of B-listers have managed to achieve movie-star status, mostly thanks to Marvel's canny marketing: Thor, Iron Man, Captain America. Other B-listers, like Green Lantern or Daredevil, haven't fared nearly as well. So you can bet that future superhero movies will be largely based on these 10 standbys, plus the occasional attempt to launch a new character.

So how can you tell when superhero movies are fizzling at last? Here are some clues to watch out for.

The next X-Men movie is an adaptation of "X-Man."
Because they've done everything else, and they figure the people who bought X-Men comics in the 1990s might still have some disposable income. For those who missed him, Nate Grey is the "ultimate mutant" created by Mr. Sinister in an alternate universe, out of DNA from Cyclops and Jean Grey. And this story has everything, including continuity so intricate that you need a PhD in X-ology to understand it. And a hero so boring that no matter who they get to play him, you'll still wind up erroneously believing that Sam Worthington played Nate Grey.

Iron Man 4 is just two hours of Robert Downey Jr. in a hot tub
Tony Stark still spits out an endless series of bon mots, many of which are still excellent. And the Jacuzzi battle between Tony and Namor is actually kind of thrilling. But the entire third act consists of Tony Stark complaining that he's getting a leg cramp.

The first post-Nolan Batman is a brooding teenage Bruce Wayne
In an effort to reinvent the Caped Crusader once again, the studio goes with a younger, edgier Bats. As Bruce Wayne, he owns a nightclub, where he DJs every night and women dance around looking vaguely like the Girl With The Dragon Tattoo opening credits. He also has his own video blog where he exposes the corruption of Gotham City — but also later at night, he puts on a Batsuit and fights crime, while saying things like "Crime is for losers." Image by Satiated Artist/WetCanvas

Zack Snyder's Superman movie does well enough that he gets to make the sequel with no studio interference
And it's two hours of slow-mo aerobics in the rain.

The Avengers 3 is all second stringers
Robert Downey Jr. is too expensive, plus he still has that leg cramp. Evans and Hemsworth are both looking too old for their characters, plus they want more money too. And somebody at Marvel believes that there's a wellspring of nostalgia for West Coast Avengers and maybe Force Works too. So why not try having an Avengers team with U.S. Agent, and Scarlet Witch, and the Black Knight? And everybody loves Spider-Woman, so throw her in there too. Plus Century! And Actually, to compensate for the lack of better known characters, the movie can always take a leaf from X-Men Origins Wolverine's book and throw in a million cameos and random shout-outs. The team of lesser Avengers can fight a team of random baddies, like the Taskmaster and Titania and the Absorbing Man. It's gold!

Reboots become oil changes
Every 3,000 miles. It just keeps them humming like hummingbirds, man. Actually, there's nothing wrong with reboots if they're done well — but as the same nine or ten properties get churned endlessly, studios will start mashing the reboot button as often as the comics publishers already do. And as the same superhero gets his or her (usually his) origin retold a half dozen times, the studios will inevitably experiment with more variation — like, maybe this time, Batman's parents get killed by the Riddler as a young crook? And Batman spends a decade trying to solve the riddle of his parents' death, until he meets the Riddler again? Or perhaps Magneto is a survivor of Desert Storm instead of the Holocaust, to bring him more up to date? There's only so many times you can retell the same origins before you have to start making some tweaks.

We get a Marvel Zombies movie.
Because like zombies themselves, the zombie genre will never die — and maybe in time, studios will sense that zombies are more popular than costumed heroes, to the point where it makes sense to turn Captain America and Wolverine into the uncanny undead. Actually, I would watch this.

Someone spends $200 million to remake Howard the Duck.
Because with CG, we can finally do Howard right. There will be more duck-on-human action and more of Howard the Duck managing a girl band — except this time, it can be more like Pussycat Dolls. After Daredevil and Fantastic Four and Punisher have all gotten another shot, you just know that someone is going to think of this unappreciated gem. George Lucas is probably dying to have a chance to update the visual effects on another of his old movies.

Thanks to Lauren, Cyriaque and Meredith for the suggestions!