In 2267, the USS Enterprise encountered extra-galactic explorers Sylvia and Korob. They likened their science to sympathetic magic on several occasions. To murder Crewman Jackson, Sylvia constructed an image of him, and in her thoughts that image was Jackson. When she killed it, and knew that it was dead, the real Jackson died. Later, she passed a small replica of the Enterprise through a candle flame, and this caused the real ship to experience dangerous levels of heat. To prevent the Enterprise from sending a rescue party, Korob then encased the model in a clear crystal, creating an "impenetrable force field" around the ship. (In fact, the field was not impenetrable; DeSalle and Chekov discovered an electrical field that weakened and would eventually have destroyed Korob's field.) (TOS: