History:
Gaseous entity that could change its molecular form, was capable of traveling across interstellar space, and could be recognized by a characteristic sickly-sweer smell. The cloud creature fed on the red blood cells of humanoid life-forms and was able to camouflage itself by momentarily throwing itself out of time sync, permitting it to be two places at once. This creature attacked the U.S.S. Farragut in 2257, killing the ship's captain and 200 of the crew. Lieutenant James T. Kirk, a crew member aboard the Farragut at the time, fired on the creature, with no effect. Years later, in 2268, the Starship Enterprise, with Captain James Kirk in command, encountered the same entity. Kirk followed the creature to planet Tycho IV, where he destroyed it with an antimatter blast.
TOS "Obsession" ; Star Trek Encyclopedia II
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