The A.V. Club's Undercover series, in which bands cover unlikely songs, is reliably fun, but it's not reliably this fun. On the most recent episode, art-metal monsters Gwar, in full costume, wedge themselves into the A.V. Club's tiny studio to knock out a sloppy, punked-up take on Kansas's Camaro-rock classic "Carry On My Wayward Son." Sadly, they leave their pressurized ...