Who’s left for the Dark Knight?

Christopher Nolan is screwed. Sure the Batman is blowing away the box office with opening sales toppling Spiderman 3 (some $155 million).

But that doesn’t mean Gotham is safe. We should be worried that Batman will have no new foes to face.

It’s no secret—with all the talk of a post-humous Oscar for Heath Ledger—that Nolan has set his Joker up as a recurring catalyst of terror and destruction throughout his bleak Gotham. But Ledger’s Joker is so downright creepy and defining, it’s impossible to recast the part.

That means there has to be a brand new demon for Bruce Wayne to fight, begging the question: Who’s next for the Dark Knight? The Harlem Globetrotters?

While other series have relied on the hokey—like Mr. Freeze and Poison Ivy—Nolan has crafted a universe that’s eerily believable. Batman’s feats are fantastical, but not implausible (especially with a billionaire’s piggy bank funding RND). Even the Scarecrow’s nerve agent isn’t wholly unimaginable.

That means no Killer Croc. No Clayface. No Penguin. Even Catwoman and the Riddler lack the gravitas needed to blend into Gotham’s seedy underbelly.

That’s a predicament Nolan better take seriously because god help him if he resorts to neon and rubber nipples.

The film, however, is excellent.