Synopsis
While trying to escape from three Romulan warships, the U.S.S. Enterprise passes through a gaseous cloud that affects the Enterprise's computer and turns it into a dangerous practical joker.

Voice Credits:

Regular Characters:

Captain Kirk	William Shatner
Mr. Spock	Leonard Nimoy
Dr. McCoy	DeForest Kelley
Scotty	James Doohan
Lieutenent Sulu	George Takei
Lieutenent Uhura	Nichelle Nichols
Lieutenent Arex	James Doohan
Lieutenent M'Ress	Majel Barrett

Guest Characters:

Romulan Commander	Lou Scheimer
Romulan crewman	Norm Prescott
Search party crewman	James Doohan
Enterprise computer	Majel Barrett

Pictures:

• Medium Sized Picture (47KB jpeg)
  
• Picture 1 (33KB jpeg)
  
• Picture 2 (33KB jpeg)
  
• Picture 3 (33KB jpeg)
  
• Picture 4 (33KB jpeg)
  
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• Picture 7 (33KB jpeg)
  
• Picture 8 (33KB jpeg)
  
• Picture 9 (33KB jpeg)
  
• Picture 10 (33KB jpeg)
  

Notes:

• This episode had the interesting distinction of being the first appearance of a holodeck on any STAR TREK series. The Recreation room that Uhura, Sulu and McCoy go into had a control console in its center that allowed the user to specify what artificial environment was to be generated.
• This episode's writer, Chuck Menville, also wrote another animated STAR TREK episode "Once Upon a Planet". Chuck Menville also wrote for several other Filmation series from 1969 to 1976.
• This episode's story was quite similar to the seventh-season STAR TREK: The Next Generation episode "Emergence". In "Emergence", the U.S.S. Enterprise-D passed through a magnescopic storm, this caused the ship's computer to briefly exhibit an emergent intelligence. Coincidentally, the computer in that episode even made use of the holodeck to act out some of the facets of its new personality, and Troi, Worf and Data were trapped and endangered there for a time. Recall that in "The Practical Joker" the U.S.S. Enterprise computer trapped Uhura, Sulu and McCoy in the holographic Recreation Room and subjected them to dangerous weather and other pitfalls.
• There is a page in this site devoted to the Romulan Ships that were featured prominently in this episode.
• A VHS video tape containing "The Practical Joker" and "The Pirates of Orion" is available for purchase from amazon.com, the online bookseller.
• "The Practical Joker" was novelized by Alan Dean Foster in Star Trek Log Six published by Ballantine Books in March 1976. In Alan Dean Foster's tale, the inflatible ship created by the practical-joking ship's computer was a Dreadnought, not a large version of the Enterprise as in the aired episode. Also novelized in the book was "Albatross" and "How Sharper Than a Serpent's Tooth".