BTS dropped their first-ever song completely in English, thrilling fans with the disco-pop «Dynamite,» Mariah Carey previewed her upcoming collections with a new track featuring an epic Lauryn Hill sample, and Iggy Azalea and Tinashe reunited to «Dance Like Nobody's Watching.»Plus, Maluma surprised fans with a new album drop, JAY-Z joined Pharrell on an ode to the black «Entrepreneur,» and Taylor Swift shared a bonus track as she reworked the album into creative «chapters.» Read on for some of