There’s something to be said for the cool, bizarre thing that happens when a band backs up someone else entirely, with not one but two recognizable styles creating either an uncanny valley effect or a very cool mash-up in the mind’s ear. You’d never know that’s Death Cab for Cutie backing up Travis Morrison on his squelchy solo debut, Travistan, but he takes them to new art-damaged heights over a beat that recalls “Love Shack,” of all things, on “Born in ’72.” And “I Just Threw Out the Love of My Dreams” is so classic Weezer that you have to wonder why that dog.‘s Anna Waronker wasn’t always their vocalist. The Afghan Whigs, meanwhile, ceded “My Curse” to Scrawl‘s Marcy Mays on their breakthrough album, Gentlemen, simply because the song was too painful and personal for Greg Dulli to sing. Bjork enlisted the overdriven bass/drum frenzy of Lightning Bolt to back up her own “Declare Independence,” while grunge godfather Neil Young needed Pearl Jam‘s driving fuzz beneath “Downtown.” And the only man whom Bono would step aside for on a U2 record — for the Casio country of “The Wanderer” — turned out to be Johnny Cash. — Dan Weiss