Jim Parsons Jim Parsons

At the risk of mixing nerd metaphors, "The Justice League Recombination" — a DC Comics-themed episode of The Big Bang Theory — promises to cause many disturbances in the force. Penny is back with Zack (Brian Thomas Smith), that Tall Drink of Manbot from last season who makes Leonard feel positively pubescent.

"The writers and I were thinking, 'Is there any reason Sheldon would want Zack for anything?'" explains executive producer Bill Prady. (Zack will likely reappear this season, but Prady isn't sure if he'll be a bona fide romantic threat.) "We started with, 'He's big and strong — maybe Sheldon needs something lifted? And that led to, 'What if Sheldon needed a Superman?'" As it happened, he did.

Each year, the boys enter the local comic-book store's costume party. "Sheldon feels, especially with his commitment to the role of the Flash, that they've been overlooked for the accolades they deserve," says Prady. (The prize: a wee trophy. The stakes: honor.) "So Sheldon says to Zack, 'How would you like to be Superman?' And Zack says, 'I don't know. It sounds like a lot of responsibility.' He's not the kind of guy normally in their world, but they come to like him."

Still, Zack's temporary anointment into the geek quad is not without its complications. With Sheldon's foolproof plan hatched, the superhero-universe shift leads to a ripple effect of indignities. Leonard, their previous go-to Superman, is downgraded to the Green Lantern. Koothrappali, normally the Green Lantern, is demoted to the ridiculous Aquaman. The indignity! Says Prady: "Koothrappali, frankly, would rather be Wonder Woman." Now that we wouldn't mind seeing.

The Big Bang Theory airs Thursdays at 8/7c on CBS. — Nisha Gopalan 

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