The Eyes of the Goa'uld were six crystals given to powerful System Lords after they defeated Anubis. Individually, the eyes were powerful, but together their power increased tenfold. Anubis eventually gathered the Eyes, using them to power a superweapon onboard his mothership. The Eyes were destroyed when the Tau'ri managed to destroy the weapon's power core when Anubis attempted to destroy Vis Uban. Considering that they were used to power Anubis' weapon, the Eyes may have been made by the Ancients as a power source. (SG1: "Full Circle", "Fallen")