“Nightwalkers” is episode five of season six of Stargate SG-1.
Major Carter receives a telephone call from an man she doesn’t know, Dr Richard Fleming, claiming to know something about what happened to Adrian Conrad, who had himself impregnated with a Goa’uld symbiote in “Desperate Measures”. He is involved in a car crash during the conversation, and his body vanishes, and it isn’t anything to do with being on a mobile whilst driving. Even though that is dangerous and can result in an accident.
A mission that takes place in Steveson, Oregon, rather than off world. Teal’c, Carter and Jonas head there, as O’Neill still has a Goa’uld symbiote from the events of “Frozen”. Dr Fleming’s lab has has a rather convenient fire, and his house has been cleaned out.
The townsfolk are acting rather strangely.