“Evolution: Part 1” is episode eleven of season seven of Stargate SG-1.
Teal’c and Bra’tac encounter many dead Jaffa of two different Goa’uld who have all apparently been killed by one warrior. Then the warrior turns up – someone in what appears to be some sort of armoured combat suit equipped with an energy weapon, who is also immune to staff weapons, and is only stopped after numerous zat blasts.
When they open the suit, they discover that the warrior has been fused to the suit, and it is a Goa’uld. The host appears to be genetically engineered – and the host seems to have died of natural causes.
The Tok’ra say that there was an Ancient device discovered by the Goa’uld, that was later used to help design the sarcophagus, that could be used to stop the warriors. Daniel heads to Honduras looking for the Fountain of Youth. And the original discoverer was attacked by Anubis, before the latter Ascended. The others decide to capture one of these warriors.
The story continues in the next episode, “Evolution: Part 2”.