Bitchcakes, Second City Theatricals, at Second City E.T.C. Molly Cavanaugh and Gillian Vigman train their sights on lowlifes and fringe dwellers with the sort of pinpoint accuracy that might make Bukowski or Burrows jealous. In this hour-long sketch-comedy show, they effortlessly negotiate bold characterizations of suburban meatheads, creepy adolescents, vomiting Michigan Avenue drunks, and low-rent authority figures. Creating a mockumentary of sorts about indie sister-sister rock act Bitchcakes, they tie together the Kids in the Hall’s gender bending with the Upright Citizens Brigade’s straight-faced absurdity.

But despite the charms of the pair’s mimicry and the seamless integration of some uproarious video sequences, Cavanaugh and Vigman seem to retreat every time they’re on the verge of some brilliant innovation. They never exhibit the ferocity their material demands; even when they’re pushing their characters to darker, more exaggerated extremes, the scenes are either disarmingly good-natured or maddeningly ironic.

And for a show that attempts to chart the rise and fall of a beloved underground music group–and that boasts a musically inclined director, T.J. Shanoff–there’s very little music on display. Cavanaugh and Vigman’s meandering meditation on fleeting fame would be fine; what scuttles their investigation is the fact that they don’t trust their instincts enough to fully perform even one of the band’s songs. Bitchcakes lines up every sacred cow imaginable…for a bloodless kosher sacrifice.