Robot Monster was written and directed by Phil Tucker. In it, Ro-Man Extension XJ-2 (aka Ro-Man) has come to Earth and used his death ray to wipe out humanity, but a handful of survivors have been injected with an experimental antibiotic serum that has spared them and they live behind a force field while Ro-Man attempts to hunt them down. He's armed with a bubble machine. But matters become complicated when Ro-Man finds himself attracted to Alice, one of the survivors.

The film was shot on a very low budget in a few days, mostly in Bronson Canyon in Los Angeles, a frequent film location, especially for science fiction, horror and western movies. George Barrows, who played the title role, got the part because he had his own gorilla suit and would work for nothing. It was originally shown in 3-D and had a score by Elmer Bernstein, who went on to write the music for more prestigious films such as The Magnificent Seven and To Kill A Mockingbird.

Robot Monster was one of many movies celebrated in such books as The Fifty Worst Movies of all Time and The Golden Turkey Awards (where it "won" the award for The Most Ridiculous Monster in Screen History) mocked on the television show Mystery Science Theater 3000. And in an era where bad movies are celebrated as well as mocked – think of the posthumous cachet attached to Edward D. Wood Jr, who made Plan 9 From Outer Space, or more recently, the cult status developed by Tommy Wiseau's The Room – Robot Monster fits right in.

CIFF artistic director Simon Weaving says he was really keen to show Robot Monster, "a much-loved Worst Film Ever Made – it's just such a hoot and perfect for outdoor viewing".

Audiences have different expectations of a cheap B-grade movie than they do of more expensive films, he says: they're willing to go along for a fun ride and not take it seriously at all.

"It's quite a social experience."

And Robot Monster's title character is, he says, "an inspired piece of nonsense", and along with the copious use of stock footage, the frequently risible dialogue and the seemingly endless shots of Ro-Man roamin' around the canyon, something viewers can enjoy. And at less than 70 minutes, the film doesn't outstay its welcome.

Viewed (slightly) more seriously, Robot Monster has themes that fit in with the concerns of US science fiction movies in the 1950s, with its echoing of Cold War and nuclear doomsday scenarios. But it's Ro-Man for which it is most remembered, and Weaving says he is one of the best bad monsters he's ever seen in a movie, along with the title creatures in Howling III: The Marsupials (1987).

More seriously, he enjoys the creatures in such films as Alien and the David Cronenberg remake of The Fly, although he says the latter is both scary and funny, even ludicrous.

Humour and horror often exist side by side, intentionally or otherwise: laughing can be our own defence mechanism against fear. Sometimes novel attempts at horror fail laughably: an attempt to make giant killer rabbits scary in Night of the Lepus (1972) was a fiasco. And what looks a lot like an ambulatory carpet in The Creeping Terror also fails in its primary purpose: to frighten an audience.

"The monster is all about fear," Weaving says.

"I totally buy into the horror film theory that we live in an insular world where we protect ourselves from life . . . We crave a little more edge, we crave danger and one way of experiencing that safely is to go to horror movies."

But sometimes we simply want to have fun. And Robot Monster is one movie that enables us to do just that.

Robot Monster (PG) is on outdoors at the National Film and Sound Archive on November 10 at 8.15pm.