"The Ambergris Element" is the thirteenth episode of the first season of the American animated science fiction television series Star Trek. It first aired in the NBC Saturday morning lineup on December 1, 1973, and was written by Margaret Armen. who wrote the earlier episode "The Lorelei Signal" and also worked on episodes for The Original Series. In this episode, Captain Kirk and First Officer Spock are mysteriously transformed into water-breathers. Source: Wikipedia (en)