From The Stargate Omnipedia
Planet containing the relics of a long-dead Ancient
SG-13 visited this world under the command of Colonel Dave Dixon, and during the standard survey was assaulted by a Goa'uld reconnaissance drone that was performing its own survey for Anubis. The device transmitted a communique to the dark lord prior to its destruction.
Shortly after Al'kesh, gliders, and dozens of troops of Jaffa had landed on the world, assaulting the team. SG-13 recieved backup from SG-1 and other teams, and was successfully extracted from P3X-666 -- but not without major casualties. Dr. Janet Fraiser was killed in the line of duty while saving the life of Senior Airman Simon Wells.
HOME TO - Unknown
FIRST APPEARED - Heroes, Part 1
Heroes, Part 1 - SG-13 arrives on P3X-666 and discover a Goa'uld reconnaissance drone performing its own recon, summoning the forces of Anubis.
Heroes, Part 2 - SG-13 is aided by SG-1 and other units, who later retreat from P3X-666 after the loss of Dr. Janet Fraiser.