Like the proliferation of the pomegranate and high-quality television programs, mashups are one of the twenty-first century’s great consolations. Mashup artists alter the instrumentation and vocals of existing tracks in order to combine two or more songs into one, and the most gifted succeed in creating soundscapes that are both astonishingly fresh and seamless. One standard-bearer is Danger Mouse’s The Grey Album from 2004, which combines the Beatles’ The White Album with Jay-Z’s The Black Album. Some recent standouts are Scott Melker’s Skeetwood Mac–a wondrous melange of Fleetwood Mac’s Rumours and rappers like 2 Chainz and Yung Joc–and “Horizon,” which features MYTHS, Grimes, and Majical Cloudz.