Stargate SG-1 - Season 2 Episode 18 -

Following on a Tok'ra tip, SG-1 goes to a planet where they find the hated Apophis, nearly dying and under attack by death-gliders. They get back with him, realizing he was tortured by a rival system-lord, with lasting harm. Apophis demands sanctuary, provided Dr. Fraiser can save his life, at least on account of the human host, but without a sarcophagus the prognosis for his symbiont is lousy; he offers all his Goa'uld knowledge in exchange for a new host, i.e. his life, revealing he was defeated by the terrible Sokar, once supreme system lord till an alliance lead ...