The Vulcan mating ritual, in which Vulcans lose all control of their carefully monitored equanimity and must mate or die. It is a chemical imbalance, a mental state, and happens once every seven years. The Star Trek: The Original Series episode "Amok Time (TOS)" was all about Spock's Pon Farr and its consequences. In the movie Star Trek III: The Search for Spock the rapidly-aging Spock supposedly goes through the Pon Farr many times, with only Saavik to help him. The Star Trek: Voyager episode "Blood Fever (VOY)" was about the Pon Farr of a Vulcan in Voyager's Engineering department, Vorik, who tried to get B'Elanna Torres to mate with him, catalysing her own Klingon mating drive.