San Anselmo-raised comic Arj Barker isn’t afraid to bring lowbrow elements into his comedy. Along with an entertaining “Flight of the Conchords” stint, he once did a flash animation series called “Arj and Poopy” with his flatulent cat. [...] Barker returns to Cobb’s Comedy Club on Thursday, June 29, for a four-day stay with six performances — although he’ll probably hang out in the Bay Area a little bit longer.