Don't get your hopes up: Fool Metal Jacket, the new ninth record from Brazilian tropicália veterans Os Mutantes, is not a tongue-in-cheek concept record based on Stanley Kubrick's legendary war flick. Bandleader and sole original member Sérgio Dias Baptista instead took inspiration for the album's title track from seeing a bunch of innocent-looking American military men heading onto aircraft. That said, if Os Mutantes did plan to write a lushly colored and buffoonish Full Metal Jacket tribute, the group would give the gambit its all. The band, originally active from 1964 to 1976 and reunited in 2006, makes kinetic, profoundly peculiar psychedelic prog-rock that feels akin to a Hair-like musical waiting to happen. If you're still sitting on the fence because of Mutantes' obscure name, perhaps two famous testimonials will sway you: Both Beck and Kurt Cobain professed to be huge fans of the band.