Marine atomic tests cause changes in the ocean's ecosystem resulting in dangerous blobs of radiation and the resurrection of a dormant dinosaur which threatens London.
A college paleontology professor acquires a newly discovered specimen of a coelacanth, but while examining it, he is accidentally exposed to its blood, and finds himself periodically turning into a murderous Neanderthal man.
Two escaped convicts are found hiding in a rocketship built by a renegade inventor, who forces them to become the crew for a trip to the Moon. Also on board, as inadvertent stowaways, are his assistant and his secretary; and none of them are aware that the inventor is actually a Lunarian explorer sent to Earth by the dying Lunar civilization and the only remaining male member of that civilization.
Aliens from Outer Space are slowly switching places with real humans -- one of the first being a young man about to get married. Slowly, his new wife realizes something is wrong, and her suspicions are confirmed when her husband's odd behaviour begins to show up in other townspeople.
A mission to Venus discovers the planet inhabited only by women led by their evil Queen Yllana. Yllana had all the men of Venus killed, now that's she met Earth men, she wants them dead, too.
A man and wife are terrorized by Mad Scientist Dr. Callistratus who was executed but has returned to life with a heart transplant. Along with his crippled assistant Carl, the 'anemic' Mad Scientist, believed to be a vampire, conducts blood deficiency research on the inmates of a prison hospital for the criminally insane to sustain his return to life.
An astronaut returns to Earth as the no-pulse host of an alien monster's embryos; he is discovered by a loony farmer who find ways to feed his new critter.
Industrialist François Delambre is called late at night by his sister-in-law, Helene, who tells him that she has just killed her husband. Reluctant at first, she eventually explains to the police that he invented a matter transportation apparatus and, while experimenting on himself, a fly entered the chamber.
A glowing brain-like creature arrives on a beach near a rocket test site via a teleportation beam. The alien communicates telepathically with the children of scientists. The kids start doing the alien's bidding as the adults try to find out what's happening to their unruly offspring.
When an abused wife grows to giant size because of an alien encounter and an aborted murder attempt, she goes after her cheating husband with revenge on her mind.
Navy Commander Alan Roberts is assigned to lead an expedition to Little America in Antarctica to investigate reports of a mysterious warm water inland lake discovered a decade earlier. His helicopter and its small party, including reporter Maggie Hathaway, is forced down into a volcanic crater by a fierce storm. They find themselves trapped in a lush tropical environment that has survived from prehistoric times.
A test pilot is missing and a search party is sent out in the jungles of Mexico; however, while searching they uncover a monster in the jungle who became this way due to a dose of radioactivity.