Star Trek (1966–1969)
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Operation -- Annihilate! 

The Enterprise crew attempts to stop a plague of amoeba-like creatures from possessing human hosts and spreading throughout the galaxy.



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Episode complete credited cast:
Joan Swift ...
Maurishka ...
Yeoman Zahra
Peter Kirk (as Craig Hundley)
Fred Carson ...
First Denevan
Jerry Catron ...
Second Denevan


The Enterprise traces a virus-like outbreak that seems to be traveling in a direct line across a planetary system. The next planet is home to Kirk's brother Sam, his sister-in-law and their young son. The Enterprise arrives too late however for Sam. They find flying jellyfish-like creatures that attach themselves to humans. They take over the victims nervous system forcing them to bend to their will. Spock finds a weapon to use against the creatures but it leaves him hopelessly blind. Written by garykmcd

Plot Summary | Plot Synopsis


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Release Date:

13 April 1967 (USA)  »

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Aspect Ratio:

1.33 : 1
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Did You Know?


This is one of only three original series episodes in which the word "damn" is used, with McCoy cursing the "damnable logic" behind the experiments designed to destroy the creatures. The only other uses of the word "damn" occur in Star Trek: Journey to Babel (1967), wherein Kirk admits he can't "damn" Spock for his loyalty by taking command of the Enterprise at the cost of Sarek's life, and in Star Trek: Court Martial (1967) where Kirk makes a log entry stating that the evidence against him is "damning." See more »


In the beginning scenes on the bridge after Uhura raises Kirk's sister-in-law, Uhura is not sitting at the communications station which places Spock's science station to her left; Spock's station can be seen in the background to her right which would place her at the navigation sub-station which is to the left of the science station. When she loses Aurelen's signal and Kirk walks away, she is now sitting at her correct station to the right of the science station. See more »


Dr. McCoy: [holding a beaker of tentacle tissue] Evidently, when the creature attacks it, uh, leaves a stinger much like a bee or a wasp, leaving one of these in the victim's body, and it takes over the victim very rapidly, and the entwining is far, far too involved for conventional surgery to remove.
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Spoofed in Futurama: The Day the Earth Stood Stupid (2001) See more »

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User Reviews

Bad Day On Deneva
10 February 2006 | by (Canada) – See all my reviews

When the Enterprise arrives at the planet Deneva they discover the population has been attacked by creatures with the ability to control humans using pain as a motivator.

There are a number of things to recommend about this episode which, in lesser hands, could easily have turned into just another dull exercise in sci-fi mediocrity. The futuristic architecture of the Denevan capital for one is a fine example of the show's use of outdoor locations. The striking design of the place (which is actually the old TRW Defense & Space Group Campus in Renondo Beach, CA. and thanks to Maverick-154 for that info) is vivid, well constructed and definitely a cut above the usually unconvincing indoor sets that producers so often had to make due with.

The alien invaders in the story (resembling some sort of pulsating tumors) are quite repellent, especially with the sound effects enhancement of insect buzzing and repulsive sucking noises. Certainly an unpleasant thing to have landing on you- which is exactly what happens to Mr. Spock here and the viewer feels real sympathy for him as he suffers with the pain of the alien infection. At the same time however we eye him with suspicion as he may just become another unwilling slave to the alien invaders and threaten the safety of the ship. Spock eventually calls upon all the Vulcan will he can muster to contain the alien influence, and here it becomes especially interesting to watch all the little indications of his inner struggle for control. His sporadic facial twitches, an especially stiff gate when he walks, and his fluctuating vocal tones all clearly indicate he's engaged in an internal war. Plus, with Spock being the type of character he is, you understand it's a struggle to maintain personal dignity as well as his self control.

Also worth noting is the inclusion in the story of Kirk's sister-in-law, nephew, Peter, and his brother, Sam, the only family members Kirk ever encountered during the 3 year run of the "Star Trek" series. Sam- or rather Sam's body as he's already dead when Kirk arrives on the scene- is also played by William Shatner wearing a little mustache.

One of the more compelling aspects of this story is the way the characters are faced with making difficult choices that will be costly for some but may accomplish the greater good for all, and this is very much a recurring "Star Trek" theme. Unable to find a method of destroying the alien presence on Deneva, Kirk must consider the cold blooded option of annihilating every living thing on the planet (including Spock and his own nephew) in order to keep the aliens from invading other worlds. When they hit upon a method by which they might destroy the creatures with intensely bright light, Spock volunteers to test that method knowing it may come at the cost of his eyesight. This story is not just about icky space creatures. It's also about moral conflict and brave sacrifice, and it's a most interesting episode all around with a terrific emotional payoff that's worth waiting for.

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