If you want to get a sense of what made Animal Collective different from other early-2000s quote-unquote indie-rock bands, listen to their cover of Fleetwood Mac’s “Dreams,” from the expanded edition of 2000’s Spirit They’re Gone, Spirit They’ve Vanished. It isn’t that it’s great—if anything, it’s more a repository of ideas than anything else. But pressed to imagine who else might’ve turned a ’70s soft-pop song into a nocturnal cloud of G-funk, psychedelia, and sound collage, and the road runs out fast. In a way, the album plays like a snapshot of where indie music was going but hadn’t gotten yet: more colorful, more eclectic, more attuned to both the accessibility of pop and the difficulty of “experimental” music (beware, listeners with a sensitivity to high frequencies), but also to the bass patterns of roots reggae and dub (“Chocolate Girl”) and the syncopations of drum ’n’ bass (“April and the Phantom”). It doesn’t always gel immediately, but it almost always does eventually. Spooky, cute, grand, and messy in the way novel ideas tend to be, Spirit was just the beginning.