Nightwalkers

S6 E5: Carter (Amanda Tapping) Teal'c (Christopher Judge) and Jonas (Corin Nemec) are sent to a small town on the Oregon coast to search for missing research scientist Richard Flemming. After the three find a partially constructed alien ship in one of the buildings Carter discovers that the zombie-like townspeople are actually Gou'ald. We learn that Immunitech is implanting Gou'ald symbiotes in the population. A symbiote is administered to Carter but Flemming's antibiotic allows her to play along until NID special operations forces arrive.