The Practical Joker (episode)

After passing through a strange space cloud, the Enterprise's computer gains an artificial intelligence that is relentlessly bent on making practical jokes on the crew.

Summary

 * "Captain's log, Stardate 3183.3. Our present mission: a routine geological survey of type 4 asteroids is nearing completion. The cruise has been uneventful and we are now approaching the final asteroid in our assigned sector a full 72 hours ahead of schedule."

The USS Enterprise (NCC-1701) is soon attacked and damaged by three Romulan vessels lying in wait on the far side of the asteroid. Scotty wants to fight but since they are outnumbered and their shields are unable to withstand another attack Captain Kirk thinks that discretion is the better part of valor. When Uhura establishes contact, the Romulan Commander claims the Federation ship trespassed into Romulan space in defiance of their own treaty. Kirk claims they did no such thing and he will file a detailed report with the Federation. The Romulan tells Kirk that the punishment for such a transgression is death. Kirk leaves and the Romulans go after him. Sulu reports an unidentified energy field in their path and the captain thinks it is just the thing to shake the Romulans so he orders the crew to batten down, they are going through.

The Enterprise manages to shake the Romulans, but unbeknownst to the crew, a cloud enters the Enterprise's computer systems. They leave, and Scott gets to work repairing the damaged systems. As the crew toasts their narrow escape, their glasses leak, and Dr. McCoy comments that they have a practical joker in their midst. Then, during lunch, the silverware bends. Spock is embarrassed when a new microscope that has suddenly appeared on his console leaves black rings around his eyes, Scott is pelted with fruits and pies from a food synthesizer, and Kirk discovers a message on one of his clean uniforms that reads "Kirk is a jerk."


 * "Captain's Log, Supplemental. Unusual incidents continue to plague our crew. Even our perceptive Mr. Spock has fallen victim to these simple minded pranks. As these little surprises have grown more and more frequent our crewmembers have found them less and less amusing. The situation has reached the point where friends are accusing friends; the entire crew is on edge, myself included."

The situation puts the entire crew on edge. They discover the source of the jokes when outrageous laughter is heard over the intercom. Spock pinpoints the source as the Enterprise itself. Kirk orders all hands to their stations to get to the bottom it. M'Ress reports that Sulu, McCoy, and Uhura are in a recreation room and do not answer the call to station. The three officers however, don't hear the call. Kirk realizes that the three crewmembers have been trapped and orders Scott to shut down the computer's logic circuits. Kirk then orders the computer to release the trapped officers and is shocked when it tells Kirk to say "Please." Scott meanwhile, is unable to shut down the logic circuits because the gravity has been shut off. Spock thinks if Scott backs off, the computer will feel less threatened and it works. Spock figures out that the subatomic particles from the energy field have invaded the computer circuits the same way bacteria infect living matter. As a result the Enterprise is having the electronic equivalent of a nervous breakdown. In the recreation room, the three officers are subjected to a snow storm and are freezing to death. Soon the bridge's air is replaced by laughing gas, which causes pain to Vulcans.


 * "Captain's Log, Supplemental. Somehow Spock managed to switch on our emergency air before collapsing from the effects of the gas. The fresh air quickly revived us, although it will be exhausted within another six hours. We must cure our computer by then or there is no telling what we will be forced to breathe next."

The ship releases McCoy and the others and Kirk lets them know how good it is to have them back, alive and well. Sulu reports that the navigation controls are not responding but they are coming about to a new heading, right into the Neutral Zone. This provokes another Romulan attack. The ship then plays a practical joke on the Romulans by creating a giant balloon shaped like the Enterprise and tricks them into firing on it, knowing they fear disgrace more than death. The Enterprise escapes, but the furious Romulans give chase. Kirk appears to be very concerned about passing through the same energy field they previously encountered, and cries out in terror when the ship changes course to do so. This is all a ruse, however; Kirk has guessed that another pass through the cloud might reverse the effect, and was only pretending to be afraid. The computer is returned to normal, after a final statement from the Practical Joker: "You tricked me Kirk. How could you?" Spock reports that all effects have been reversed. Uhura reports strange transmissions from the Romulan warships, which followed them through the field. It seems they are beginning to be affected by the same symptoms as Kirk's crew was. McCoy asks, "Should we tell them how they can reverse the effects of the field, Jim?" Kirk says, "Yes, but later. Let's not spoil their fun just yet," and everyone gets a good laugh.

Memorable quotes
"Go ahead and laugh! Big joke! I'll bet you two are responsible for this, eh?"

"Hey, wait a minute! We didn't cause this to happen!"

"Tell that to the Captain! I'm reporting the both of you just as soon as I...!"
 * - Scotty and Arex

"Captain, crewmembers McCoy, Sulu and Uhura are still in the recreation room and do not answer the call to stations."
 * - Lieutenant M'Ress

"Spock, quiz the central computer about McCoy and the others."

"Yes, captain. Question: why are we unable to communicate with crewmembers McCoy, Sulu and Uhura?"

"Answer: that is for me to know and for you to find out."

"Did I hear that right?"

"Affirmative. The dysfunction is more severe than I thought."
 * - Kirk, Spock, and the computer

"Okay, whoever you are! So we fell for your juvenile joke! Now get us out!!"
 * - McCoy

"I order you to release crewmembers McCoy, Sulu and Uhura immediately."

"Say please."

"P-l-e-a-s-e."

"Say... pretty... please... with sugar on."
 * - Kirk and the computer

"Time for a nap, old girl. Captain's orders."
 * - Scotty

"We're giving it a mighty go with the crowbars though!"
 * - Scotty

"It's no-o-t fair-r-r-r-r-r..."
 * - The Enterprise computer, having lost the energy picked up from the energy field previously passed through

"Turn off those food synthesizers! We're knee-deep in desserts and they're still pouring out!"
 * - Romulan Commander

Background Information

 * This is the second consecutive installment to feature the concept of a practical joker, following the introduction of Ari bn Bem in the episode immediately prior to this one,.
 * This episode also includes the first appearance of a holodeck in Star Trek history (and summarily, the "holodeck malfunction"), although it is known here as a recreation room. Gene Roddenberry had intended to introduce a holodeck-type room in the third season of Star Trek: The Original Series; however, budget constraints prohibited it. (Inside Star Trek: The Real Story, p. 404)
 * The editors of Trek magazine collectively scored this episode 4 out of 5 stars (a rating that they termed "very good"). (The Best of Trek #1, p. 111)
 * In the unofficial reference book Trek Navigator: The Ultimate Guide to the Entire Trek Saga (pp. 179 & 180), co-writers Mark A. Altman and Edward Gross both individually rate this episode 2 out of 4 stars (defined as "mediocre").
 * This episode was novelized by Alan Dean Foster in Star Trek Log 6, which was first published in.
 * The "inflatable starship decoy" was used again – to even greater comic effect – in John M. Ford's novel How Much for Just the Planet?.

Video and DVD releases

 * UK VHS release (CIC Video): Volume 7, catalog number VHR 2557,
 * As part of the The Animated Series DVD collection

Starring

 * William Shatner as Captain Kirk
 * Leonard Nimoy as Mr. Spock
 * And


 * DeForest Kelley as Dr. McCoy

Also starring

 * George Takei as Sulu
 * Nichelle Nichols as Uhura
 * Majel Barrett as:
 * M'Ress
 * Computer voice
 * James Doohan as:
 * Scott
 * Arex
 * Enterprise Engineer

Guest stars

 * Lou Scheimer as the Romulan Commander
 * Norm Prescott as the Romulan Crewman