An ex-major forces a scientist to develop a invisibility formula, with which he plans to create an invisible army and sell it to the highest bidder. However there are side effects to the formula.
The head of a major cosmetics company experiments on herself with a youth formula made from royal jelly extracted from wasps, but the formula's side effects have deadly consequences.
In one of his rare performances without Bud Abbott, Lou Costello plays a rubbish collector and inventor. When radiation in a nearby cave turns his girlfriend into a giantess, antics ensue as he tries to shrink her using one of his inventions.
A pathologist experiments with a deaf-mute woman who is unable to scream to prove that humans die of fright due to an organism he names The Tingler that lives within each person on the spinal cord and is suppressed only when people scream when scared.
A backwoods game warden and a local doctor discover that giant leeches are responsible for disappearances and deaths in a local swamp, but the local police don't believe them.
Trapped on a remote island by a hurricane, a group discover a doctor has been experimenting on creating half sized humans. Unfortunately, his experiments have also created giant shrews, who when they have run out of small animals to eat, turn on the humans.
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.
Teenagers from a small town and their high school science teacher join forces to battle a giant mutant spider, living in a cave nearby and getting hungry.
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.
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.
Glenn Manning, "The Amazing Colossal Man," believed dead after falling from the Hoover Dam, reemerges in rural Mexico, brain damaged, disfigured, and very angry.
When the first manned flight to Venus returns to Earth, the rocket crash-lands in the Mediterranean near a small Italian fishing village. The locals manage to save one of the astronauts Colonel Calder, the mission commander. A young boy also recovers what turns out to be a specimen of an alien creature. Growing at a fantastic rate, it manages to escape and eventually threatens the city of Rome.
A group of scientists travel to a remote island to study the effects of nuclear weapons tests, only to get stranded when their airplane mysteriously explodes. The team soon discovers that the tests have given rise to crabs mutated into intelligent, impervious, telepathic giants intent on increasing their numbers by breeding, then travelling to populated areas to feed, and which do not intend to be stopped by their discoverers.
The arrival in a small mountain town of a dissheveled stranger launches a series of murders committed by some sort of animal. As the town doctor and his daughter attempt to help the stranger, the sheriff investigates the murders; and they uncover a sinister experiment involving two rogue scientists, a car accident victim, his wife and children, and a serum that causes a man to turn into a ravaging werewolf.
A marine biologist and a government agent investigate mysterious deaths and rumors of a sea monster in a secluded ocean cove, and find themselves involved with a marine biology professor conducting secretive experiments, international spies trying to steal his secrets, a radioactive light on the sea bottom, and the malevolent thing which guards it.