The Omeyocan are "the enemy of my enemy" (the Goa'uld), but surprisingly, they are never seen or mentioned again in the series, leaving a major plot thread dangling for years.
While the rest of the team thinks Daniel has been vaporized or teleported, he has actually been shifted —he is invisible and intangible to everyone except Teal'c, whose Jaffa symbiote allows him to sense Daniel's presence. The Grandfather Connection [S3E21] Crystal Skull
The emotional core of the episode is Daniel’s relationship with his grandfather, . Nick is an eccentric archeologist living in a psychiatric institution because he claimed to have seen "Giant Aliens" through a similar skull in Belize decades earlier. The Omeyocan are "the enemy of my enemy"