In the film the model of the octopus had only six tentacles due to budget constraints. To overcome this marine physical handicap, the model was always partially in the water at any one time. Don’t believe me? Check it out!
1956: EARTH vs. THE FLYING SAUCERS
The design of the saucers had an animated section added into the top and underside. Flutes were also incorporated into the design so that audiences could see that the saucer was moving. Ray simply used old recording wire on which to suspend the saucers to give the illusion of flying. The Capitol and the Supreme Court buildings which were miniature sets cost a mere (by today’s blockbuster standards) $1500 each. The Washington Monument came in at a bargain price of $500. Ray’s dad made the saucers from aluminum which was then anodized to give them a matt finish so they wouldn’t reflect light.
Harryhausen always involved himself in the pre-production film's story concept & script development as well as art-direction, design, story-boarding and other aspects of his films.