In an interview, Jeff Morrow said that no one in the cast saw the title monster until they went to the film's premiere in Morrow's home town. Producer Sam Katzman had contracted with a low-budget model-maker in Mexico City to construct the "Giant Claw," and no one in the cast or crew had any idea it would come out looking as bizarre as it did. Morrow said the audience roared with laughter every time the monster made an appearance. He wound up slinking out of the theater in embarrassment before the film was over so no one who knew him would recognize him.
The producers originally planned to use a stop-motion model created by Ray Harryhausen for the bird. Due to budgetary limitations, they used a marionette.
It has been reported that the marionette of the "Giant Claw" monster, made by a model-maker in Mexico City, cost producer Sam Katzman a mere $50.
Some of the stock footage of panicked crowds running was taken from El día que paralizaron la Tierra (1951).