Star Trek: Season 2, Episode 3

The Practical Joker (21 Sep. 1974)

TV Episode  -   -  Animation | Action | Adventure
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Ratings: 6.8/10 from 113 users  
Reviews: 2 user | 2 critic

The computer of the Enterprise gains partial sentience and starts playing practical jokes on the crew.


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Title: The Practical Joker (21 Sep 1974)

The Practical Joker (21 Sep 1974) on IMDb 6.8/10


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Episode cast overview:
Capt. Kirk (voice)
Mr. Spock (voice)
Dr. McCoy (voice)
Sulu (voice)
Uhura (voice)
M'Ress / Computer voice (voice)
Scott / Arex / Search party 7 Crewman (voice)


To avoid a confrontation with Romulans, Kirk orders the ship through a unknown energy field. They escape the Romulans, but the energy field has changed the ship's computer into a prankster. It begins pulling more and more complicated practical jokes on the crew, finally to the point of endangering McCoy, Uhura, and Sulu on the Recreation Deck. Besides those three's lives, the Romulans re-appear and threaten the ship. The practical-joking computer actually helps distract the Romulans for a short while, but then the ship is once again set upon. Kirk tricks the computer (using reverse logic) into re-entering the energy field, which restores the computer to normal, but makes the Romulans' computers into pranksters instead. Written by Tony-B4

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Release Date:

21 September 1974 (USA)  »

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Technical Specs

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Aspect Ratio:

1.33 : 1
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Did You Know?


This is the first appearance of a holodeck - called a Recreation Deck - in the "Star Trek" universe. See more »


The Enterprise deploys an inflatable ship 20 times the size of itself. Even though it is presumably a thin skinned balloon, it would take a lot of material to create. There would have to be large compressed air tanks within it and the amount of air or whatever gas is used would need to be 20 times the volume of all the air needed to keep the enterprise crew alive. See more »


Dr. McCoy: When I get my hands on the clown who's behind all this, I'll put him in sickbay for a week!
Main Computer: Temper, temper!
See more »


Featured in Drawn to the Final Frontier (2006) See more »

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User Reviews

Star Trek: The Practical Joker
18 December 2013 | by (United States) – See all my reviews

"Practical Joker" might be considered one of the sillier episodes of the cartoon of the original series of Star Trek, but I think it has some cool things to offer fans. Like the initial attack by Romulan warbirds who claim that the Enterprise has invaded their space--in turn breaking the Neutral Zone treaty--while studying asteroids during a routine mission, the "rec room" (clearly an inspiration for the Holodeck on The Next Generation) where Doctor McCoy, Uhura, and Suli become trapped and toyed with, and an inflatable Enterprise surprising the Romulans who halt a potential attack on the real vulnerable Enterprise. The plot involves, believe it or not, the Enterprise "having a nervous breakdown" (as explained by Spock as a ship behaving illogically, therefore perplexing his logical mind) after the ship travels through an energy field to avoid further damage by the Romulans. The main computer of the Enterprise begins playing practical jokes on the crew and laughing because of them! Like the food machines suffering malfunctions (at one point, a machine spits out a load of food at Scotty, including a whipped cream pie that splats on his face!), or a release of nitrous oxide causing all on board to suffer the laughing effects of the gas: when Kirk orders Scotty to shut the logic computer off, it retaliates by causing the gravitational systems to usurp their efforts! The rec room situation (where McCoy, Uhura, and Sulu are stuck and cannot get out, with the computer ultimately creating a whiteout snowstorm location for them to suffer before a hedge maze appears with them stuck right in the middle!) is one of the most dangerous that is featured in the episode (…which mostly seems geared towards laughs instead of suspense). It is resolved easily, while Kirk outsmarts his ship's paranoid (and practical joking) computer by feigning terror about traveling back through the energy field that caused their current situation. The Romulans seem to have used the asteroid study, claiming invasion of their space, merely as a tactic to engage in battle with the Enterprise, so Kirk's using them as a comic foil by way of a pursuit through the energy field is an amusing counter to their lopsided three-to-one advantage and attack approach. I just had a lot of fun watching this one: it is more aimed at children and features a lot of jokes played on Kirk and crew (Spock's eye-viewer gag, the dribbling drinking glasses, and laughing gas sequence are all amusing touches, as is the computer itself laughing gleefully at the crew). I think this is a good example of how the cartoon format can be beneficial in presenting imaginative moments that a feature television series (at that time) weren't quite able to do, like the rec room's creation of locations through programs, or the gravitational reaction of the computer leaving Scotty floating and needing to crawl out of Engineering on all fours, upside down, across the ceiling, just to exit safely. A cartoon did have advantages: ideas that weren't economically feasible on a television format were possible in animated form.


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