The Fifth Race (S02E15)

Dr. Daniel Jackson and the rest of the SG-1 team travel to an ancient room that houses alien inscriptions, in an attempt to decode alien languages discovered by a probe. When Col. Jack O'Neill peers through a viewer in the ancient room, he is trapped momentarily in its grasp. Shortly afterward, alien words begin peppering his speech. Before long, his entire brain is taken up with a superior knowledge virtually indecipherable to the rest of the SG-1 team. Daniel is certain that O'Neill now possesses the knowledge of the Ancients, the alien race that invented the stargates, but he realizes that the knowledge is too complex for human brains and will likely cause O'Neill to lose his sanity. In an attempt to save himself, O'Neill must access his subconscious mind to discover ones with a greater knowledge than his own, ones who might also have important knowledge about the destiny of mankind. (Metro-Goldwyn-Mayer (MGM))