Michael Rosenbaum by Michael Courtney/The CW Michael Rosenbaum by Michael Courtney/The CW

On Thursday's episode of Smallville (8 pm/ET, The CW), Clark Kent ( Tom Welling) gets a look at what life would have been like if his rocket ship never arrived on Earth. Brainiac ( James Marsters), last seen zooming away with Clark's Krypto-cousin Kara ( Laura Vandervoort), is trying to set such a Kal-El-free scenario in motion. Clark, having a bit of a pity party over Lana's continued zombieness, isn't so sure that's such a bad idea. "Since the day I arrived, all I've brought is suffering and death," he says. "Meteor freaks, phantoms, Brainiac. If I'd never reached Earth, none of them would've ever been here."

Right on cue, his own version of It's a Wonderful Life plays out thanks to his Kryptonian dad Jor-El, who enables him to see what a non-Clark world would be like. And let's just say it's not a pretty picture. Lex Luthor ( Michael Rosenbaum) is president of the United States, with Milton Fine - aka Brainiac - as his chief of staff. And their plan to consolidate power won't have a happy ending for the human race. (Hint: the episode's title is "Apocalypse.")

The episode - directed by Welling - is the series 150th and also has a few Easter Eggs:

" In the alternate reality Chloe ( Allison Mack) is engaged to a guy named George Dean - a shout out to previous TV Supermen George Reeves and Dean Cain.

" Likewise, Kara - running the Department of Domestic Security for President Lex - is going by the name Linda Danvers, which was once Supergirl's secret identity in the comics.

" Clark is present in the fantasy sequence (nobody knows who he is and they're all too busy to really press the issue) and his first meeting with Lois Lane ( Eric Durance) is a sweet homage to Christopher Reeve and Margot Kidder's meet cute-and-clumsy from Superman: The Movie. Lois is a Pulitzer Prize-winning reporter and she works with Clark to expose Lex's big plan. There are lots of hints at their future romantic relationship. Says executive producer Al Gough: "This just proves that that no matter what the reality is, Clark and Lois are ultimately destined to be together." - Rich Sands