ACL ’09: The Yeah Yeah Yeahs Sparkle Our Imaginations And Karen O Gets Crazy.

Dressed like a character belonging more to Pan’s Labyrinth than anything of the natural world, Karen O led the Yeah Yeah Yeahs through a fantastical, epic performance at Zilker Park last night.

And it was all thanks to O’s doing. Beyond charismatic and magnetic, Karen O’s on-stage persona is a mixture of childlike fascination and well-studied punk rock execution. The most charming thing about it all, though? Through all the ridiculousness–the stuffing of the microphone in her mouth, the jumping around, the freezing in place, the three different variations of the same outfit she wore, the spitting of her water into the air–even Karen O couldn’t help but find the humor hidden beneath.

Giggling throughout the set–a giggle befitting a maniacal evil-doer with a childlike fascination with shiny objects–she and the rest of the band led the charged, anti-Kings of Leon crowds at Zilker through a set spanning a wide range of the band’s catalog.

But, without a doubt, the highlight came with the band’s toned-down, acoustic performance of its biggest song to date, “Maps,” with which the entire audience seemed to sing along as O’s own vocals barely raised above a whisper.

But as much as this performance is likely to be remembered for that one tender moment, the other, freakier portions of the set–like when two giant, inflatable eyballs were unleahsed among the crowds, like when Karen O smacked her microphone repeatedly against the stage like it was a whip, like when Karen O appeared toward the end of the set in a mask even Lady Gaga would envy (imagine The Scarecrow from Batman Begins, as imagined by Kanye West)–were what gave it its true character.

And then, just as suddenly as it had started, the hour-plus set came to an end, the beyond-charming O jumping and waving goodbye at the crowd, and the crowd respnding in kind.