A sloppy bootlegged collection of clips or a clever piece of guerrilla marketing from Columbia Pictures?

That’s the question being posed this week as a purported “teaser trailer” from David Fincher’s upcoming “The Girl with the Dragon Tattoo” noirfest makes the rounds online.

But folks are swearing that the jittery red-band footage is legit, and just the sort of viral hackery that its protagonist Lisbeth Salander (played by Rooney Mara, opposite Daniel Craig, in this American version of novelist Stieg Larsson’s brilliant Swedish trilogy) would perform with wicked stealth.

If we need to tell you the computer-whiz-helps-wrongly-convicted-journalist plot, you’ve truly been asleep at the pop-culture switch for the past two years.

But here’s the most intriguing part. The trailer offers a glimpse into the Trent Reznor-composed soundtrack, via a pulsating industrial updating of Led Zeppelin’s “Immigrant Song.” Featuring, on vocals, a banshee-volumed Karen O of Yeah Yeah Yeahs renown, hitting every star-screaming Robert Plant note from the propulsive original. And if you’re still reeling from witnessing Reznor, in a pricey suit, stalk up to the podium to accept his soundtrack Oscar this year (for Fincher’s “The Social Network”), then your jaw will scrape the floor when you hear what he and O are up to now.

“Blown away by the response to the Dragon Tattoo red band trailer,” Reznor just tweeted. “Please try to see a real version in a theater if you can ... we designed the sound for an in-theater experience.”

For more information, visit www.nin.com.