Despite young Demi Lovato's precocious resume—the affiliation with a certain purple dinosaur, the Disney star turn—the spectacle of their maturation into a fantastically spunky pop singer was still a sight to behold. Amid the teen-ingenue gloss, Lovato always cut an authentic figure, and when their humongous voice and independent streak flourished it was all but a fireworks display. Now the singer can rage with Fall Out Boy, explore bi-curiosity (“Cool for the Summer”), and slam-dunk a vocally gymnastic power ballad. If “Stone Cold” doesn't make you shiver, you're not listening closely enough.