He found that the human body made a very good host and was easily maintained through the use of the sarcophagus, a device capable of rapid healing, even from death. He was searching for a new type of host for his dying race. The First World, Earth, was found by the Goa'uld Ra 10,000 years ago. The Goa'uld have existed for a very long time, but they have been most successful in exerting their power since they took humans as hosts (their first hosts, the Unas, evolved on the same planet, P3X-888). The term 'Goa'uld' is applied to both the symbiote itself and the blended host, since the host of a Goa'uld is prevented from exerting his own personality after the blending. A symbiote, as it is also known as, invades a host, usually human, through the back of the neck (some have been known to go through the front) and blends into the host's biological structure, attaching itself into the brain and thus gaining access to the host's knowledge and voluntary muscular system. The Goa'uld are aquatic parasitic creatures that evolved into intelligent, but extremely evil, beings.