The alien costume featured in Night of the Blood Beast was the same as the one used in another Roger Corman film, Teenage Caveman (1958). This was done to save money, as the Cormans often tried to incorporate existing sets, costumes and other elements from previous films into new ones for financial savings. Varno said the Corman brothers were so conscious of their spending that "'cheap' was the main word in their vocabulary". The monster costume scenes in Teenage Caveman and Night of the Blood Beast were shot within about two weeks of each other. The costume was modified slightly for Blood Beast. Ross Sturlin wore the costume for the scenes in both Teenage Caveman and Night of the Blood Beast. Filming was very difficult for Sturlin because it grew extremely hot inside the costume during the exterior shots. John Mathew Nickolaus, Jr. was director of photography for the film, and Jack Bohrer was the production manager. Daniel Haller, who went on to become a film director himself, worked as art director on Night of the Blood Beast. Haller did much of the manual construction work on the set himself, and brought a trailer in to the sound stage so he could sleep there and between work sessions. Among the props he built was the rocket-ship, the frame of which was made of plywood that had been cut into circles, then covered with a plastic sheet and spray-painted to look metallic. Haller also created blood cells that the characters looked at under a microscope, and the baby aliens (which resembled seahorses) they looked at under a fluoroscope. Alexander Laszlo composed the music for the film.Almost the entire crew went on to work on Attack of the Giant Leeches with the Corman brothers and Kowalski.
Shot in seven days.
This was released in one of American International's prepackaged double features. It was paired with Roger Corman's She Gods of Shark Reef (1958), which had been sitting on the shelf for a year and a half.
The film was featured in a 1996 episode of the comedy television series, Mystery Science Theater 3000.
Produced by exploitation filmmaker Roger Corman and his brother Gene, it was one of the first films directed by Bernard L. Kowalski and was written by first-time screenwriter Martin Varno, who was 21 years old. It starred several actors who had regularly worked with Roger Corman, including Michael Emmet, Ed Nelson, Steve Dunlap, Georgianna Carter and Tyler McVey.
It took Varno six weeks to write the script, the original working title of which was Creature from Galaxy 27. The story was partially influenced by the real-life Space Race and the Howard Hawks film The Thing from Another World (1951). Screenwriters Jerome Bixby and Harold Jacob Smith gave Varno uncredited assistance with the dialogue.
With a budget of about $68,000, it was shot over seven days. All of the interior scenes were shot at sound stages inside Kling Studios. Most of the exterior shots were filmed at Bronson Canyon, a set of caves at Griffith Park in Los Angeles that was a popular shooting location for low-budget films. The exterior scenes of the tracking station were shot at a television station on Mount Lee, not far from the Hollywood Sign. Varno said it was the first television station built in Los Angeles, but was only being used for emergency broadcasts when Blood Beast was filmed; it had also been used during World War II to send information and propaganda to the Allied Forces' overseas allies. Varno secured permission to film there simply by calling the city of Los Angeles and asking permission, something he said nobody else considered trying because they assumed the city would not allow it. Varno was familiar with the station because his father, Roland Varno, appeared in the first dramatic television show released in Los Angeles and it was transmitted from that station. For the Blood Beast shoot, Los Angeles charged a fee of $8 per actor to shoot at the station, but the crew could be any size. All shooting took place outside the station and none inside. Most of the station night scenes there were shot during the day, and the film crew often had to find shadows to shoot in or block out the sun to give the impression of nighttime. Producer Gene Corman said of the shooting: "That was one of the more mobile units I've ever been involved with. Normally, everybody chases the sun; we were chasing the shadows."
Following dissatisfaction with his treatment by the Cormans, screenwriter Varno pursued two successful arbitration cases, one of which was for underpayment. The other was in response to Gene Corman's original story writing credit, even though Varno claimed to have written the entire story himself.
Jerome Bixby, the science fiction screenwriter who wrote It! The Terror from Beyond Space (1958), was originally approached for the job, but Bixby was working on another project and recommended his close friend Martin Varno for the job. Varno, the son of veteran actor Roland Varno, met with Roger and Gene Corman, who discussed with him what Varno called "some sort of a weird idea for the picture". They offered Varno a couple hundred dollars for the job, which was below the minimum compensation rates known as "scale", but Varno was not part of the Writers Guild of America at the time and did not know about the guidelines. He accepted the offer and signed a contract. Although Varno had a rough idea it would be a low-budget film, he said the Cormans set no specific guidelines for him: "I gave them the impression that I knew pretty much what I was doing, and they sort of got the idea that I wasn't going to use 50,000 extras and things."
The Cormans cast the film together with director Bernard L. Kowalski, who was 28 years old at the time. Kowalski also directed Roger Corman's Hot Car Girl. Night of the Blood Beast was one of Kowalski's first directorial credits and his first science fiction film, although he later went on to direct Attack of the Giant Leeches.
When asked what star Ed Nelson remembered about the film during a 2003 interview, he admitted, "Not much", but he said Roger and Gene Corman were very knowledgeable about film and treated the material "light-heartedly".
Both Roger and Gene Corman were present for most of the film's production and involved creatively as well as financially. Gene was more involved with running the day-to-day operations while the more experienced Roger Corman supervised and provided guidance to both Gene and Kowalski. Some rewriting was done as the filming progressed, and director Bernard L. Kowalski called it a collaborative process that involved himself, the Cormans and the whole crew. Varno, however, said he was not happy with how the filming process went, and that the Cormans changed dialogue and story elements without his consultation or permission. He said it reached the point where he called his agent and said, "I am not working for these [expletives] any more! I am sick and tired of the whole thing!"
Varno said he received uncredited assistance from his friends and fellow screenwriters Jerome Bixby and Harold Jacob Smith, the latter of whom won an Academy Award for Best Original Screenplay for the film The Defiant Ones (1958). Varno ran lines and ideas by both men and sought advice. Smith in particular inspired lines for the speech made by the monster at the end of the film, in which the creature discusses how the human characters consider him the embodiment of evil simply because he is different from them. Varno said much of that dialogue from Smith, however, ended up getting cut from the final film.
One of the primary themes of the film, as embodied in John Corcoran's attempts to defend the alien creature, was that simply because someone or something is ugly or different does not necessarily make it evil. However, the script also followed a common trait of most horror films of the 1950s that even somewhat understandable monsters are not entirely sympathetic, and the Blood Beast creature proves itself evil by impregnating Corcoran against his will and pursuing world domination.