Mac DeMarco's second album—first if you only count Rock And Roll Nightclub as an EP—came out last year, and its messy-but-glorious songs were some of the best of 2012. The Canadian performer (and oh, he does perform) has professed an interest in Weezer in interviews, so we weren't too surprised that he and his band grabbed "Undone—The Sweater Song" and whipped it into something special. You can find DeMarco's own songs on the excellent 2. Enjoy.