The sound you heard when Animal Collective performed their tune “Summertime Clothes” on the Late Show with David Letterman on May 7 was that of a highly creative underground band crashing into the mainstream. After Letterman held up a copy of the band’s latest album Merriweather Post Pavilion, adorned with a simple repeating pattern, the talk show host quipped: “look for it in the wallpaper department of your favorite department show.”

When the cameras swung over to the trio onstage, things got even weirder.

Behind equipment stands glowing a fluorescent green, the three musicians started into “Summertime Clothes,” which is by turns a piece of catchy synth pop and an out-there sound collage of what sounds like a slot machine vomiting coins paired with Native American-like warrior whoops.

On the far left, Geologist (Brian Weitz) was immersed in wringing sounds from some kind of electronic instrument in front of him, while bandmates Avey Tare (David Porter) and Panda Bear (Noah Lennox) provided vocals that circled one another like a couple of Blue Angels at an airshow.

In the background, four individuals cocooned in some sort of fabric wriggled around like people trying to escape from a tent that had collapsed on each one of them. It was enough for Letterman to point to the “dancers” after the performance and remark to his bandleader, “Paul, do you have anything for the trick or treaters?”

Though it’s considered their most accessible work, Merriweather Post Pavilion still exemplifies a brand of music that’s hard to predict. The opening song, “In the Flowers,” is a hybrid of ’60s psychedelia and contemporary electronica that undergoes an explosion of sound halfway through, including a drumbeat that pounds like a heart on a pulse-quickening drug.

“Guys Eyes” is an unexpected mix of Beach Boys-like vocals over a drumbeat and watery sound effects. Meanwhile, “Lion in a Coma” grafts aboriginal sounds – is that a didgeridoo? – to a dense, processed pop song, while “Brother Sport” begins as a technology assisted a capella number until an almost world music rhythm joins the mix.

Somehow, despite its experimental impulses, Merriweather Post Pavilion is being accepted by the mainstream: it peaked at 13 on the U.S. Billboard Album 200 chart after coming out this past January.

To view the clip of Animal Collective performing “Summertime Clothes” on the Late Show with David Letterman, visit www.youtube.com/watch?v=ehLEHxvl9rA.

ANIMAL COLLECTIVE play 7pm Wednesday, May 27, at Henry Miller Library, located 25 miles south of Carmel on Highway 1, Big Sur. Sold out. 667-2574.