Though they’ve been making music for several years, very little is known about the LA duo 18+. But their trilogy of mixtapes — which ended with last year’s incredible MIXTAP3 — speaks for itself, as it cycles through murky, lyrically disturbed R&B and hip-hop. 18+ recently released two of the best songs off that tape, “Horn” and “Crow,” as their first official single, and now the latter of those has been paired with a music video. Sliding through grainy footage, the clip is divided into three visual sections that switch in rhythm with the insistent, repetitive crow sample that helps to build the minimalist beat. Eventually flies crawl across the screen, adding to the pretty unease of the song. There is plenty of subtle weirdness thrown in, too, such as the random smiley face that pops up without explanation, or the fact that the first frame is a paused YouTube screen for the “Gangnam Style” video. It answers no questions, just weaves an extra layer into this musical mystery.