Star Trek – The Devil In The Dark

★★★★★ March 9, 1967 Season 1 Episode 25

If you want to see where we are…and you missed a few…HERE is a list of the episodes in my index located at the top of my blog. 

This show was written by Gene L. Coon and Gene Roddenberry

William Shatner’s father died during the making of this episode. Please check the IMDB notes below about that. 

This is the fourth excellent episode in a row. I’ve seen a video of a 1990s Star Trek convention of Leonard Nimoy saying this episode’s closing banter between Spock and Kirk was one of his favorite scenes to perform. He noted, “It was a wonderful moment which defined the relationship and defined the whole Spock character’s existence and his attitude about himself.”

 I like the fact that the episode is not about one specific character but evolves around the trio handling an alien problem. Also, it’s nice to see an episode that doesn’t only happen on the Enterprise.

The Enterprise arrives at a mining colony on Janus VI in order to kill a beast called the Horta, which has been killing miners, jeopardizing the exportation of the ever-important pergium (an element for energy). As the miners continue drilling deeper, it seems to be upsetting the monster more and more. Spock soon discerns that the monster is silicon-based, not the type of life form that the crew is familiar with.

The Devil In The Dark" (S1:E25) Star Trek: The Original Series Episode  Summary

In the beginning, everyone hates the Horta… they fear it and loathe it. But Spock’s mind meld and Kirk’s understanding soon changes this tune for everyone. People are often afraid of what they don’t understand. This episode reveals to us that, if we hope to find peace with what we don’t understand or take issue with, the first step is communication.

There is not much action in this one but a compelling episode and is a very good first-season episode. During the episode, Kirk wanted the creature killed but Spock wanted it alive. Spock augured to no avail but things started to change once he met the Horta. 

Just a quick note on a director. Ralph Senensky was told he was going to direct this episode and was sent the script but then told it would be another episode…yesterday’s This Side of Paradise. 

The reason I mention this is that Ralph has a great site where he talks about all of the different Star Trek and other TV shows (including the Twilight Zone and Waltons) he directed. If you have time check it out…he is 99 years old but still posts on his site

From IMDB:

In his book “Star Trek Memories”, William Shatner identified this as his favourite episode, because his father died during filming and Leonard Nimoy’s delivery of the mind meld lines made him laugh. He thought it was “exciting, thought-provoking and intelligent, it contained all of the ingredients that made up our very best Star Treks.”

Janos Prohaska, the creator of the Horta costume, actually wore it into Gene L. Coon’s office, as if to say “Look what I designed”. Coon said “That’s great! What is it?”, and Prohaska said “I don’t know. It can be whatever you want.” Coon replied “I’ll write a script around it”, and he wrote this episode in four days so the costume could be used.

Arthur C. Clarke once remarked, in 1995, that of the Original Series, the only episode he could recall was this one, stating that “It impressed me because it presented the idea, unusual in science fiction then and now, that something weird, and even dangerous, need not be malevolent. That is a lesson that many of today’s politicians have yet to learn.”

When William Shatner, on the set, got the call from his mother informing him about his father’s death, the crew was ready to shut down production, but he insisted on continuing. During the rest of the day, Shatner took comfort in Leonard Nimoy, and cinematographer Gerald Perry Finnerman, whose father had died on a movie set less than seven years before.

William Shatner was in Florida for his father’s funeral while nearly all of Spock’s “mind meld” scene with the Horta was shot. His screen double is shown from behind in several of the shots and all of Kirk’s “reaction” shots were made after he returned.

This episode was the first time McCoy used the phrase, “I’m a doctor, not a (blank)” when Kirk asks him to help the Horta, finishing the line as, “I’m a doctor, not a brick layer!” An earlier version of this phrase is used in “The Corbomite Maneuver,” when McCoy says, “What am I, a doctor or a moon-shuttle conductor?”

Gene Roddenberry was impressed with the way this episode explains the behaviour of a Star Trek “monster,” citing the instalment as “a classic example of doing this right” as well as “one of our most popular episodes.” He went on to say, “The Horta suddenly became understandable [….] It wasn’t just a monster-it was someone. And the audience could put themselves in the place of the Horta… identify… feel! That’s what drama is all about. And that’s it’s importance, too… if you can learn to feel for a Horta, you may also be learning to understand and feel for other Humans of different colours, ways, and beliefs.”

In a book about Star Trek, it was reported that after William Shatner returned from the funeral, to put everyone at ease, as he was trying to do his lines following Mr. Spock’s mind meld with the Horta and his cry of “AHH! PAIN! PAIN! PAIN!”, Leonard Nimoy just spoke the words, so Shatner told him to do it again with feeling. When “Spock” again said “AHH! PAIN! PAIN! PAIN! ” Shatner yelled out, “WILL SOMEBODY PLEASE GET THIS VULCAN AN ASPIRIN!”

“No Kill I” was the name of a Star Trek-themed punk rock band.

This episode includes only one actress, who appears for a few seconds and has no lines. This is the only episode with no female speaking parts.

The unbroken Horta eggs were toy bouncing balls painted gold.

NBC announced that Star Trek would be renewed for a second season next fall, during the closing credits of this episode on 9 March 1967.

This is the only episode in the original series in which the distinction is drawn between “phaser one” and “phaser two.”

This episode marks the first and only time an episode begins without the Enterprise or its crew being involved in the teaser scenes before the main credits.

Gene L. Coon’s original script featured a different material as the base of the Horta, but researcher Kellam de Forest changed it to silicon, as the original choice seemed to be even theoretically impossible.

Actor Barry Russo, appearing as Lt. Commander Giotto, also appears in Star Trek: The Ultimate Computer (1968) as the character Commodore Robert Wesley.

The Star Trek: Deep Space Nine (1993) novel “Devil in the Sky” is a sequel of sorts to this episode.

This episode was originally scheduled to be filmed before Star Trek: This Side of Paradise (1967), with Ralph Senensky assigned to direct it, but during pre-production the two episodes and the directors were switched because Gene L. Coon thought “Devil” would be a tough assignment to first-time Trek director Senensky.

The clubs used by some of the Janus VI colonists during their hunt for the Horta appear to be of the same design used by Kirk during his fight with Spock in the transporter room in Star Trek: This Side of Paradise (1967).


The Enterprise travels to the planet Janus 6 to assist the mining colony there. Kirk, Spock and McCoy beam down to the planet where Chief Engineer Vanderberg tells of a creature loose in the mine tunnels killing some of his men. The monster seems to appear out nowhere then disappears just as quickly. Finding that the creature, known as a Horta, lives in a newly opened part of the underground mining complex, Spock uses the Vulcan mind meld to determine why it is killing the miners.


Here are some CGI effects they have made into this episode


William Shatner … Captain James Tiberius ‘Jim’ Kirk
Leonard Nimoy … Mister Spock
DeForest Kelley … Doctor Leonard ‘Bones’ McCoy
Ken Lynch … Vanderberg
James Doohan … Lieutenant Commander Montgomery ‘Scotty’ Scott
Brad Weston … Appel
Biff Elliot … Schmitter
George Allen … Engineer #1 (as George E. Allen)
Jon Cavett … Guard
Barry Russo … Giotto
Lee Allen … Janus IV Miner (uncredited)
Tom Anfinsen … Civilian Engineer (uncredited)
Bill Blackburn … Lieutenant Hadley (uncredited)
Frank da Vinci … Lt. Osborne (uncredited)
Dick Dial … Sam (uncredited)
Robert Hitchcock … Miner (uncredited)
Bob Hoy … Horta (uncredited)
Monty O’Grady … Miner (uncredited)
Eddie Paskey … Lieutenant Leslie (uncredited)
Janos Prohaska … Horta (uncredited)
Al Roberts … Roberts (uncredited)
Ron Veto … Security Guard (uncredited)



Author: Badfinger (Max)

Power Pop fan, Baseball fan, old movie and tv show fan... and a songwriter, bass and guitar player.

24 thoughts on “Star Trek – The Devil In The Dark”

  1. Crazy to think that Ralph went from doing Star Trek and The Twilight Zone to The Waltons. In other words he goes from Beam Me Up Scottie to Goodnight John Boy, Grandma and Mary Ellen! Impressive and great job here Max!

    Liked by 3 people

  2. Another great-looking episode, Max. The comparison between the original and the CGI-enhanced footage is interesting as well and really shows how good the original was!. And Ralph Senensky still posting content at age 99? Wow, I guess directing keeps you young!

    Liked by 1 person

  3. Computer’s running kinda slow today ,so am being a bit delayed posting and reading others. Anyway, good ‘moral’ to it from the sound of this (I guess maybe Star Trek was like TZ in that, most episodes driving home a good message). I think it shows the way I feel about most ‘bad’ wild animals, majority of them are just going about their business and not especially problematic to us if we leave them alone.

    Liked by 2 people

    1. After watching animal youtube channels…even King Cobras want nothing to do with us…if we leave them alone…they will us for the most part. It’s all about respect.

      Liked by 2 people

      1. Just a few days back I read a post saying Coral Snakes were by far the most dangerous (in terms of toxicity of venom) snake in Arizona…but there had never, ever, been a reported accidental bite. If you don’t try to pick it up or have it as a pet, or stomp on on it barefoot, you will not be bitten. Period.

        Liked by 1 person

      2. Yep! They will not chase after you unless you are near their eggs…just like most other animals. Leave them alone and they will you.


  4. This is an episode with a huge message you’re right. In it, the ideal is reached between human and nature, where both acknowledge a symbiotic relationship. Spock comes in handy in a lot of ways. I like the way the creature knew how to spell lol. You found so much good detail on this episode. One of these days if there is ever time I will check out Ralph’s website.

    Liked by 1 person

  5. Well, maybe I’m in the minority here, but the Horta costume made me LOL. A guy crawling around under a lumpen carpet!? However, that to one side (swept under the rug?) it is a very thought provoking episode., one I enjoyed revisiting a few nights back. It still holds up well, as a lot have commented on.

    Liked by 1 person

    1. No I get what you are saying! I’ve noticed something also…after this season the effects get a little worse…and then in the third you could tell their budget was slashed. The storeis and acting saved this show no doubt.

      Liked by 1 person

      1. Strange how the show had a record of success, maybe not earth shattering ratings-wise, but the studio budgeteers still ripped the budget up more though most looks like it is recycled- store fronts from the studio back lot, Vasquez rock, the costumes were mostly already there; and if you needed one for a female character that was only about half a yard of material used, at most. Minimum requirements there!

        Liked by 1 person

  6. You’ve done an excellent job of describing elements that make this my favorite episode for the message – that with open minds, we can come to understand and empathize with living beings that look very different from humans (and all that implies.) I did not realize until you mentioned it that there were no female speaking parts in this episode, though the Horta seems to have a traditionally female role of protecting her children.

    Liked by 1 person

    1. Thank you!
      It is a great episode. I like how Kirk and Spock both say “kill it” at different times but both wait to do the responsible thing.
      The Horta in this one was the star female.

      Liked by 1 person

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