Test space rockets exploding at liftoff and increased reporting of UFO sightings culminate in a direct attempt by alien survivors of a dead, extra-galactic civilization to invade Earth from impervious flying saucers, using ray-weapons of mass destruction.
Starship C57D travels to planet Altair 4 in search of the crew of spaceship "Bellerophon," a scientific expedition that has been missing for twenty years. They find themselves unwelcome by the expedition's lone survivor and warned of destruction by an invisible force if they don't turn back immediately.
Scientists surgically transform the Creature into an air-breather, but being able to live on land is not enough to make him comfortable with humans. Enraged, he turns his wrath on anyone who comes near as he desperately tries to return to the deep-water world where he truly belongs.
A rogue scientist near a small desert town arouses the suspicion of the town's doctor when his lab assistant is found dead from a case of acromegaly, which took only four days to develop. As the doctor investigates, aided by the scientist's new female assistant, they discover that something is devouring local cattle and humans in increasingly large quantities.
A giant octopus, whose feeding habits have been affected by radiation from H-Bomb tests, rises from the Mindanao Deep to terrorize the California Coast.
Dr. Eric Vornoff, with the help of his mute assistant Lobo, captures twelve men for a grisly experiment; His goal to turn them into supermen using atomic energy. Reporter Janet Lawton, fiancée of the local lieutenant, vows to investigate Vornoff's supposedly haunted house.
Two fishing scout pilots make a horrifying discovery when they encounter a second Godzilla alongside a new monster named Anguirus. Without the weapon that killed the original, authorities attempt to lure Godzilla away from the mainland. But Anguirus soon arrives and the two monsters make their way towards Osaka as Japan braces for tragedy.
In a tributary of the Amazon, a monster – half-man, half-fish – is captured and placed in a reservoir in a Florida national park to be observed by scientists.
A uranium prospector is eating a peanut butter sandwich in the desert where atom bomb tests are being done. He becomes radioactive, and helps the FBI break up an enemy spy ring.
Japan is thrown into a panic after several ships are sunk near Odo Island. An expedition to the island led by Dr. Kyohei Yamane soon discover something far more devastating than imagined in the form of a 50 meter tall monster whom the natives call Gojira. Now the monster begins a rampage that threatens to destroy not only Japan, but the rest of the world as well.
As a result of nuclear testing, gigantic, ferocious mutant ants appear in the American desert southwest, and a father-daughter team of entomologists join forces with the state police officer who first discovers their existence, an FBI agent and, eventually, the US Army to eradicate the menace, before it spreads across the continent — and the world.
When scientists exploring the Amazon River stumble on a “missing link” connecting humans and fish, they plan to capture it for later study. But the Creature has plans of his own, and has set his sights on the lead scientist's beautiful fiancée, Kay.
A Scotsman abruptly breaks off his engagement to pretty Kitty and moves to his uncle's castle in the Scottish highlands. Kitty and her aunt follow Gerald a few weeks later, and discover he has suddenly aged. Some mysterious things happen in a maze made from the hedges adjoining the castle.
A scientist develops a formula which will cause animals to regress to the form of their primitive ancestors, and tries it on himself with disastrous results.