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X the Unknown (1956)

Approved | | Horror, Sci-Fi | May 1957 (USA)
0:53 | Trailer
A radioactive, mud-like creature terrorizes a Scottish village.


, (uncredited)


(story and screenplay)



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Cast overview, first billed only:
Edward Chapman ...
John Elliott
Insp. 'Mac' McGill
LCpl. 'Spider' Webb
Jameson Clark ...
Jack Harding
William Lucas ...
Peter Elliott
Peter Hammond ...
Lt. Bannerman
Marianne Brauns ...
Zena, the Nurse
Ian MacNaughton ...
Haggis (as Ian McNaughton)
Michael Ripper ...
Sgt. Harry Grimsdyke
John Harvey ...
Maj. Cartwright
Edwin Richfield ...
Soldier Burned on Back
Jane Aird ...
Vi Harding
Norman Macowan ...
Old Tom
Neil Hallett ...
Unwin (as Neil Hallet)


British Army radiation drills at a remote Scottish base attract a subterranean, radioactive entity of unknown nature that vanishes, leaving two severely radiation-burned soldiers... and a "bottomless" crack in the earth. Others who meet the thing in the night suffer likewise, and with increasing severity; it seems to be able to "absorb" radiation from any source, growing bigger and bigger. What is it?? How do you destroy a thing that "feeds" on energy? Written by Rod Crawford <puffinus@u.washington.edu>

Plot Summary | Plot Synopsis


It rises from 2000 miles below the earth to melt everything in its path! See more »


Horror | Sci-Fi


Approved | See all certifications »

Parents Guide:





Release Date:

May 1957 (USA)  »

Also Known As:

Het onbekende  »

Company Credits

Production Co:

,  »
Show detailed on  »

Technical Specs


Sound Mix:

(RCA Sound Recording)

Aspect Ratio:

1.37 : 1
See  »

Did You Know?


The U.S. version shown on TV for many years contained only introductory music under the Warners Brothers title, with no opening title music. The British version, featured on later DVD versions, contained James Bernard's opening title music. See more »


Near the end, when John is backing up the jeep to the pit, he is sweating profusely. In the next scene his face is dry. See more »


Dr. Adam Royston: Now, Mac, how would you go about killing that?
Inspector McGill: What is it?
Dr. Adam Royston: It's a particle of mud. But by virtue of its atomic structure it emits radiation. That's all it is. Just mud. How do you kill mud?
See more »


Featured in TJ and the All Night Theatre: X the Unknown (1979) See more »


Serenade for Strings in E Major, Op. 22: V. Finale: Allegro vivace
Written by Antonín Dvorák
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User Reviews

Good, grim, post-Quatermass horror/sci-fi
30 January 2002 | by (London, England) – See all my reviews

The plot: In the remote Scottish Highlands, a living radioactive mass seethes out of the depths of the earth and kills everyone in its path as it seeks fresh radioactive energy. Luckily an American scientist is about the place and kicks the 'thing' back down from whence it came.

X the Unknown, while not having the innate intelligence of the Quatermass movies, is a good example of 1950's British pulp science-fiction cinema. While most of its American counterparts visited fantastic worlds inhabited by outlandish monsters and gorgeous 'space-babes', X the Unknown was a truly British effort: our monster was dollop of mud out of a hole in the ground doing a slow crawl around a dingy moor.

It's effective though. It has the same austere, grim intensity which made the Quatermass movies so memorable. The film also benefits from moody, high-contrast black and white photography, a typically acerbic score from James Bernard, and a good cast; Leo Mckern turns in a very good, naturalistic performance, much like his turn in The Day The Earth Caught Fire.

I first saw this movie when I was about six and the extraordinarily graphic scene depicting the monster 'devouring' a hospital doctor gave me a few... err....sleepless nights (there's a particularly ruthless zoom-in to the poor guys hand as it expands and melts!). Perhaps I should have stuck to Bugs Bunny.

Overall, a decent chiller, well directed by Leslie Norman (late father of the superb British film critic Barry Norman).

One last memory of a six year-old's first viewing of this picture: I remember sitting there stunned and horrified as the end credits rolled; I was not looking forward to a good nights sleep. The statutorily paternal BBC announcer came on and cracked the following nervous joke: "Well, I'll never eat cheese on toast again" (see the film and you'll know what he meant). I laughed with relief and my childhood was thus saved a terrible trauma! Thanks Uncle Beeb.

29 of 31 people found this review helpful.  Was this review helpful to you?

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