Mac Miller had a stellar year, releasing GO:OD AM, his most mature and well-rounded artistic statement to date. It was proving hard to pick just one song from that cohesive and cleverly sequenced album, but then Alchemist came along and solved all our problems. The fire-alarm beat goes hard, and Migos and Mac waste no time in killing it. An unlikely combination, but a winning one. Can we get a mixtape, please?—Constant Gardner