Iggy Azalea crash-landed into the pop world with 2014's “Fancy,” her giddy, boastful collaboration with pop songbird Charli XCX, and the Australian MC's Southern-inspired drawl, elliptical rhymes, and blonde ambition have propelled her to pop domination. She details her come-up over stormy EDM on “Work,” while the wobbly, distortion-heavy beats of “Mo Bounce” make her tales of debauchery sound even more fun. Her hookups with pop's brightest lights see her shape-shifting: She brings streetwise style to Britney Spears' glittering “Pretty Girls,” adds heat to Zedd's old-school banger “Boom Boom,” and shakes up Jennifer Lopez's frantic “Booty.”