"The Practical Joker" is the third episode of the second season of the American animated science fiction television series Star Trek, the 19th episode overall. It first aired in the NBC Saturday morning lineup on September 21, 1974, and was written by American television writers Chuck Menville and Len Janson who together also wrote the first season episode "Once Upon a Planet".Set in the 23rd century, the series follows the adventures of Captain James T.