Goa'uld

The Goa'uld are a species of Eusocial parasitic sapients that are the first reveiled and primary villians for much of the Stargate Franchise. Physiologically, most Goa'uld resemble lampreys about thirty centimeters long and are capable of entering the body of a lifeform and commendeer control of it. They also increase the lifespan (futher augmented by Devices such as Sarcophagi) and strength of the individual, as well as being able to improve general health. Using the Stargate network, seeded civilization of human serfs and jaffa and reverse engineered ancient technology, the Goa'uld established a fuedal empire over most of the Milky Way holding power by control of technology and through Religion, posing as Gods.