By Michael Ausiello
Updated March 18, 2010 at 06:40 PM EDT

Here’s a second exclusive photo from Chuck‘s May 24 season finale featuring — major spoiler alert — the first-ever music video by Jeffster! (The first image can be viewed here.) If you guessed correctly, pat yourself on the back and then read on for more scoop on the video and the pivotal role it plays in Chuck‘s two-hour season finale.

“It’s the worst music video of all time,” declares executive producer Josh Schwartz, who declines to reveal the title of the song. He does, however, offer these two clues: The track was once featured in a horror Western-themed movie, and it ties into the episode’s big climax. “The way the original song was used in the movie is the way we’re using it here,” hints Schwartz. Adds fellow exec producer Chris Fedak: “The song narrates the action.”

What’s the song? What’s the horror movie? Speculate away in the comments section. And then pick up the new issue of Entertainment Weekly for more scoop on Chuck‘s sure-to-be-legendary May 24 season-ender!