Sobek was a Goa'uld System Lord who was known on Earth as an Egyptian god of fertility. He barely managed to maintain enough holdings to keep his title of System Lord. In desperation for territory, he once attempted to steal one of Bastet's worlds. Bastet and her ally, Kali, retaliated swiftly. Sobek tried to sue for peace, and Bastet and Kali pretended to accept. However, at their celebratory feast he was swiftly executed. His head supposedly decorates Bastet's palace in Bubastis. (SG1: "Summit") (RPG: "Roleplaying Game")
Another account has Sobek survive into 2003, where he made his way to the Ilempiri homeworld, seeking control of a parasite trapped in a chamber on the planet. To this end, bounty hunter Aris Boch was hired to capture SG-1 so that Sobek could take Doctor Daniel Jackson as his new host to translate the chamber. However, Sobek's control over Daniel was weakened by both the parasite within the chamber and Sobek's own need to keep Daniel's consciousness more active than the Goa'uld preferred in order to access the subtle nuances of Daniel's linguistic knowledge. These factors, combined with his greater age and lack of a sarcophagus, eventually forced Sebek to abandon Daniel before his death, leaving Daniel relatively unharmed from his time as a host (SG1: "Siren Song").
Another account of Sobek's demise is set around the start of a System Lord war. While the others fought amongst themselves, he made his way to an Ancient planet in search of treasure that he had heard mention of in the past. He sent his First Prime Hem'nok and a group of his Jaffa to the surface to breach the central temple. When they failed to find a way in, Sobek used the main weapon of his ship to make an opening. Instead, the temple collapsed under its force. The destruction activated the giant Android guardian Kotah, who immediately fired upon Sobek's vessel with power from his sword. The attack destroyed Sobek's ship and killed him along with it. (Stargate: "Daniel Jackson 2")