Black Mountain plays heavy music, but it would be shortsighted to call it a heavy rock band. That’s because the Canadian five-piece takes that heaviosity in so many directions. Black Mountain’s latest, IV, is a druggy spaceship ride to Mars from its pulpy cover art to the buzzing, synth-laden interior. The sci-fi-meets-psych sound is bolstered by the fact that the guitars—while still present—lurk in the dark spaces. They come out for the eight-minute opener, “Mothers of the Sun,” which deftly maneuvers between Pink Floyd acidity and the expansive iciness of early Genesis. Black Mountain follows its prog ambitions while still finding room for pop melodies, as vocalists Amber Webber and Stephen McBean sound like they were raised on 1970s FM rock, tuning in from a cult compound. That bridge between eeriness and tunefulness is what makes IV such a compelling listen. Here it’s safe to drink the Kool-Aid.