The ordeal undergone during the Water of Life ceremony, in which a Bene Gesserit must transmute a deadly poison within her own body to survive and become a Reverend Mother. The candidate's consciousness turns inward, her timesense slows, and she perceives the molecular structure of the poison, which she must then change through sheer force of trained will. Those who fail to transmute the poison die. Success grants access to Other Memory and the full powers of a Reverend Mother. Among the Fremen, the ceremony used the exhalation of a drowning sandworm as the poison.