Last night there was an "American Idol" first: The first time Nirvana was ever performed on the show's stage.
The theme of the night was "Birth Year Songs" and Casey Abrams decided to take on Kurt Cobain and Co.'s "Smells Like Teen Spirit" from 1991.
With a little extra growl in his voice and a guitar in his hands, the bearded 20-year-old got praise from judges Jennifer Lopez and Randy Jackson for taking a risk with his performance -- though J.Lo said it was a "little bit screamy-screechy" at times.
Steven Tyler loved it, saying "That's the goop the great stuff is made of, and you got it."
Check out the performance above -- are you feeling it?