'American Idol' judge Kara DioGuardi takes it off for bikini girl

Rocker shocker Kris Allen's win last night wasn't the only jaw-dropping moment last night on "American Idol."

Bikini girl (aka Katrina Darrell) returned to the "Idol" stage last night bearing new assets to pick up an award for "best attitude."

But the big surprise came when Darrell again performed her horrific rendition of Mariah Carey's "Vision of Love." She sang it during auditions early this season (yes, in a bikini) when she verbally sparred back and forth with judge Kara DioGuardi.

DioGuardi had the last laugh Wednesday.

During Darrell's performance last night, DioGuardi appeared on stage to outsing her, and then ripped off her clothes to mock the puzzled "Idol" contestant. The video speaks for itself: