On its latest record, We Kill Everything (definitely something that you shouldn’t let your mom know about, which is, of course, one more reason to buy it), GWAR tells the story of its attempt to escape Earth through the Portal Potty. Only problem is that it’s broken. So the metal band might as well, er, kill everything. Its legendarily gross onstage theatrics include feeding concertgoers and band members into huge prop dinosaurs and anuslike monsters. But don’t worry: If you’re not eaten alive, you’ll merely be doused with the blood of those being slain on deck. GWAR gets omnicidal with Godhead and Puya at 8:15 p.m. at the 9:30 Club, 815 V St. NW. $15. (202) 393-0930. (Javi Guerra)