Spencer Krug made his name with the Montreal indie warriors Wolf Parade, but he sounds even more dementedly great as the dungeon master of Sunset Rubdown. As you might guess from the title, Dragonslayer is a feast of Seventies-style prog: Krug can't stop singing about dead butterflies and sacrificial virgins in his mad-priest bark. "Idiot Heart" opens with psychedelic guitar, then adds xylophone...