“Your favorite rappers’ corpses couldn’t match up to my importance,” A$AP Rocky boasts. To put yourself above the sainted ghosts of Biggie and Pac, you’ve got to either be really good, crazily ambitious or just plain high — and on his second studio LP, the Harlem rapper is all these things and more. At.Long.Last.A$APtakes the gritty East Coast classicism and syrup-drippin’ Houston screwiness of his killer 2013 debut, Long.Live.A$AP, and adds an extra level of psychedelic sprawl via a newfound taste for acid. “I introduce her to this hippie life/Make love under pretty lights,” he raps on the lustrous “LSD.” Producers like Danger Mouse, Kanye West, Mark Ronson and Rocky himself keep the expansive vibe rolling with a sound that’s at once tough and transporting — from the gospel-steeped “Holy Ghost” to the interplanetary ass-shaker “Electric Body” to the Rod Stewart-sampling soul fantasia “Everyday” (featuring Miguel). Even at his trippiest, Rocky makes sure things never swirl off in a haze of incense and peppermints, with steely lyrics that often focus on inescapable truths: “Richer’s growing richer/The poor’s growing weak/My brother died in the streets/May he rest in peace,” Rocky raps on “Max B.” His head’s in the stratosphere, but his mind is heavy with reality.