Ex Hex formed the way bands used to: by alchemical accident, in a carpet-lined cubbyhole drowned out by the hardest of Washington, D.C.'s hard-core freaks. You'd almost never know there's a pedigree here — the female power trio banged out its practiced-yet-imperfect October debut Rips (Merge) in two weeks, binging on 16th notes and redlining through proto-punk and power pop like it's 1979 — but these scruffy mutts are purebred. Particularly Mary Timony (ex-Autoclave, ex-Helium), an indie-rock lifer whose reward for two decades of outlasting trends was a moment in the sun as the second singer/guitarist on supergroup Wild Flag's eponymous 2011 debut, which also happened to be its swan song. As if starved for vitamin D, Timony stole the spotlight back from former bandmates Carrie Brownstein and Janet Weiss, whose ballyhooed reunion as Sleater-Kinney was presumed to be Wild Flag's sudden cause of death. Rips calls for a second autopsy: a dozen potent reminders of the powerful combination that is three musicians and three minutes. Guesting on the A.V. Club series "HateSong," Timony recently mused for 2,500 words about how much she loathes John Mayer's "Your Body Is a Wonderland." (Money quote: "There's bands like the Ramones that do so much with so little, but a person like John Mayer just does so little with so much.") As a culture critic, the brevity is lost but the bravado remains. Sub Pop gonzo rocker King Tuff headlines. Tickets $12.