Katy Perry is one of pop's most versatile stars. "Waking Up in Vegas" harnesses pop-rock crunch to tell its story of Sin City debauchery; the swirling "Save as Draft" brings power ballad dramatics to an email inbox. Perry's collaborators have helped her play with funk and hip-hop, too; the Calvin Harris/Pharrell team-up "Feels" blends deep grooves with ska bounce, and she explores trap's sparse textures with Migos on the frantic "Bon Appetit".