Season 4 Episode 8 - The First Ones

While conducting an archeological dig on planet P3X-888, Daniel Jackson makes a remarkable discovery: a primordial Goa'uld symbiote, an ancient, predatory version of SG-1's parasitical enemies. Before he can bring back his sample however, his team is attacked by an Unas. One team member is killed and Daniel is dragged off into the wilderness by the giant primitive creature. Learning of Daniel's disappearance, O'Neill leads a rescue mission to the planet. Upon his arrival, he discovers that SG-11 has been almost wiped out - only Hawkins survived - and the planet's water supply is teeming with Goa'uld symbiotes. While O'Neill and Teal'c struggle with the possibility that one of their men may have been inhabited by a Goa'uld, Daniel is dragged further into the wilderness by his captor. Gradually, he begins to understand a few words of the creature's language. The Unas, a juvenile whose name seems to be Chaka, saves Daniel's life when he's attacked by a symbiote.