The blood of a primitive fish exposed to gamma rays causes a benign research professor to regress to an ape-like, bloodthirsty prehistoric hominid.


Jack Arnold


David Duncan





Complete credited cast:
Arthur Franz ... Professor Donald Blake
Joanna Moore ... Madeline Howard
Judson Pratt ... Police Lt. Mike Stevens
Nancy Walters ... Sylvia Lockwood
Troy Donahue ... Jimmy Flanders
Phil Harvey ... Police Sgt. Powell
Helen Westcott ... Nurse Molly Riordan
Alexander Lockwood Alexander Lockwood ... Professor Gilbert Howard
Whit Bissell ... Dr. Oliver Cole
Ross Elliott ... Police Sgt. Eddie Daniels


A college professor acquires a newly discovered specimen of a prehistoric fish. While examining the find he is accidentally exposed to it's blood, turning him into a murderous Neanderthal. Written by Jeremy Lunt <>

Plot Summary | Plot Synopsis


Chills! Thrills! See more »


Horror | Sci-Fi


Approved | See all certifications »

Parents Guide:

View content advisory »

Did You Know?


Early in the movie when driving in the neighborhood, you can see the left side of the Munsters home See more »


Dragonflies do not 'buzz' like houseflies or bees; their wing beats are too slow. See more »


Sylvia Lockwood: [Seeing a giant dragonfly at the window, she screams]
Professor Donald Blake: Don't open the door! It'll escape!
Sylvia Lockwood: Who cares?
Professor Donald Blake: I care! I want it!
Jimmy Flanders: Well, what is it?
Professor Donald Blake: I don't know! We'll find out when we catch it!
See more »

Crazy Credits

The one-sheet poster lists "The Beast" as the sixth cast member. See more »

User Reviews

All things considered, it has a certain respectability
27 July 2019 | by hung_fao_tweezeSee all my reviews

Made in 1958, here is a general reworking of all the came before. It's Dr. Jekyll/Mr. Hyde married to any werewolf movie. Yet, it never entirely verges into camp or silliness. The performances are strong, even from the dog. The music, though borrowed from other movies like 'The Incredible Shrinking Man' and 'Tarantula', is used effectively giving the action a boost where needed.

The special effects were nothing special. The transformation from man to beast and back again were smoother than 'The Wolfman', but the resulting creature was almost too obviously a rubber mask. Closeups do kill the effect somewhat so they filmed him at a distance which pulled the visuals back into plausibility. Much of it works well.

But why was this made? As noted, there's nothing new. It is played as a very straight forward no nonsense monster movie. It has its moments of real horror but it also doesn't even try push boundaries. If you had to judge it against all other of this genre, it's a C+.

A good solid movie for a rainy day and popcorn.

4 of 4 people found this review helpful.  Was this review helpful to you? | Report this
Review this title | See all 51 user reviews »

Frequently Asked Questions

This FAQ is empty. Add the first question.






Release Date:

17 December 1958 (USA) See more »

Also Known As:

Monster in the Night See more »

Company Credits

Show more on IMDbPro »

Technical Specs


Sound Mix:

Mono (Westrex Recording System)

Aspect Ratio:

1.85 : 1
See full technical specs »

Contribute to This Page

Recently Viewed