A$AP Rocky’s appearance on Late Show with David Letterman could’ve gone a lot of ways. The young Harlem star might have brought Florence Welch and her powerhouse pipes with him (via “I Come Apart”), or done something ennui-dripping with Lana Del Rey (via “Ridin'”), or shown up with his motley Mob (via Coachella). But the rapper born Rakim Mayers had something else in mind. Two “somethings,” in fact: 1) a throne, and 2) a double-song set featuring a turntable destroyer A-Trak, drum machine brutalizer AraabMUZIK, and old school DJ Clark Kent. “Here we go,” said Letterman with perhaps a slight air of trepidation. The camera turned to Rocky, sporting a peacoat and a white snapback, perched atop an opulent seat fit for a king. He stayed seated for most of his new album’s titular track, “Long Live A$AP,” but hopped for his high-energy Skrillex-produced hit, “Wild for the Night.” As the throne slid to the side of the stage, the beatwise trio did their thing, offering up what were it not for Fallon would probably have been the most virtuosic hip-hop performances in late night history. It was strange, stylish and pretty great — so par for the Rocky course.