Host

From SGCommand

Hosts are creatures which can serve as survival methods for symbiotes and parasites. The Goa'uld and Tok'ra both require hosts to survive, but their methods of acquiring hosts are extreme opposites. The Goa'uld forcibly steal hosts from their homeworlds, taking complete control of their bodies and forcing them into what is described as a living hell. In sharp contrast, the Tok'ra do not take hosts, but rather acquire their consent before entering. The Goa'uld insist that nothing of the host survives, but this has been disproven on a number of occasions.

While in a host, a Goa'uld and Tok'ra can increase the hosts intelligence and strength, and give it a nigh perfect immune system. They also secrete naquadah into their hosts blood stream (though wild Goa'uld on P3X-888 do not do this). The symbiotes can also make their hosts eye glow at will, and usually speak in a deep, booming voice.