The Goa'uld are a race of parasites,they mainly take human hosts who can be identified by glowing eyes and a very deep voice. They have posed as false gods from ancient cultures for millenia, mainly egyptian.
The Goa'uld took millions of people from Earth and scattered them around the galaxy before Earth rebelled and burried the Stargate. The Goa'uld use Jaffa as slaves to carry symbiotes until they mature and are able to be placed inside a human host.
When a Goa'uld symbiote is placed inside a body it so powerful that it takes over the mind of the host so that practically nothing remains of the original mind. There are many Goa'uld "leaders" called the System Lords.
They all control seperate territories in the Galaxy and spend most of their time fighting each other
to gain new territory or to defend that which they allready posses.
