S3, E4: The SG-1 team discovers a room containing the corpses of a league of Goa'uld who challenged the system lords. One holds a tablet; after Dr. Daniel Jackson touches it he begins to hear voices and see nightmarish visions. Medical tests indicate Daniel is suffering from schizophrenia. Whatever is interfering with his mind however soon transfers to Teal'c ΓÇö with far more deadly consequences. As the Goa'uld parasite leaves Daniel's body Daniel hears the voice of the dead Ma'chello declaring death to the Goa'uld. Daniel realizes that he was infected by Ma'chello's Goa'uld-killing parasite a theory borne out by Teal'c's rapid deterioration. Believing the tablet holds the key to Teal'c's survival the team brings it to the lab. As they open the tablet though the parasites ooze into medical officer Dr. Janet Fraiser Maj. Samantha Carter and Col. Jack O'Neill. Carter proves immune but with parasites inside them Fraiser and O'Neill deteriorate rapidly. Gen. Hammond has no choice but to seal the lab off with the three inside.