Is Yeah Yeah Yeahs lead singer Karen O from another planet? Perhaps, and I think this is the closest photographic evidence will come to proving it. Alien, human or robot, it doesn't really matter, because the firebrand rocker positively killed it onstage on a cool Saturday afternoon for Day 2 of Lollapalooza. We've got reviews of the first two days up right now and Day 3 is on its way. You can also click here for our photo gallery that captures all three days worth of action.