This also has Hans Conried (who did work in both film and TV, including a lot of voice acting, such as Snidely Whiplash from the Rocky and Bullwinkle Show, and King Azaz the Mathemagician from The Phantom Tollbooth film); Max Showalter (uncredited in Elmer Gantry and The Music Man and who was in TV from 1948-1983); Mimi Gibson (a child actor, long since retired and happily raising llamas according to Wikipedia); and Charles Herbert (another long-retired child actor, perhaps best known as the son in the The Fly, who seems to be active in science fiction conventions).
The voiceover at the beginning (I do hate those) sets it up:
This is the Salton Sea in Southern California, a strange phenomena in which Nature has placed 400 square miles of salt water in the middle of an arid desert. In the desert close to the shore of the sea the government has established one of its most important naval research bases. In the laboratory on the secluded south tip of the base top secret atomic experiments are carried out under rigid security controls. While at the airfield, planes working under the direction of the parachute test unit, leave on daily missions for the jump area over the Salton Sea, where Navy personnel hit the silk in the government's continuous researching of parachutes to meet the ever-increasing demand of modern flight. On May 17, in the early afternoon, an earthquake occurred in the desert area. Its force was strong enough to be felt at the research base, even though its epicenter was 10 miles away in the wild rock formations 350 feet deep below the surface of the Salton Sea. However, less than 2 hours after the earthquake, the base was back to normal operating procedure. Lt. Hollister of the parachute test unit was preparing to make the last scheduled jump of the day. Hollister was a veteran of over 300 test flights, and -for him- this was to be one more routine jump.favorite quote: "No, I haven't seen any creature. Just plain foolishness."
Meanwhile, on the Salton Sea, crewmen Johnson and Sanders were headed out to meet Lt. Hollister. And for them this was to be one more routine pick-up.
I actually like this one. There's a nice mix of character development and personal relationship sub-plots in with the mystery and terror of the monster. It also avoids most of the sexist pitfalls that bother me.
via Daily Motion:
Moria gives it 2 out of 5 stars and says, "It competently, if unremarkably, shuffles the basic tropes". 1000 Misspent Hours calls it original, but says, "The Monster that Challenged the World, huh? The Monster that Challenged My Patience is more like it! The atomic snails are some incredibly cool critters, but this movie’s biggest weakness is that they’re hardly ever onscreen."
HT: Need Coffee