Katy Perry plays with magic -- plus the conventions of trap music -- on her new single, "Dark Horse." The track features a Juicy J rap verse and a beat that sounds straight out of Atlanta (by way of Dr. Luke and Max Martin). "It's kind of a juxtaposition. It's got me, a pop artist, with a little bit of an urban kind of hip-hop-flavored background soundtrack to it, and the lyrics are kind of witchy and dark, as if I was a witch warning this man not to fall in love with me, and if you do know I'm going to be your last," Perry told MTV. (Shouts, meanwhile, to Juicy J for dropping a Ke$ha reference in his verse: "Her love is like a drug.") Listen above. Perry's new album, "Prism," is out on Oct. 22.