Confined to a mental hospital, young Kirsty Cotton insists her supposedly dead father is stuck in hell, controlled by sadomasochistic demons after being betrayed by his evil, occult-obsessed wife, Julia. Few believe Kirsty, except the thrill-seeking Dr. Channard, who is intrigued by the young woman's lurid stories. So when Kirsty and fellow patient Tiffany head to hell for a rescue, Channard and Julia are close behind.
University professor George Kingsley is struck by gangsters while crossing the street, leaving him with brain damage and one of the gangsters, Cannon, paralyzed. Kingsley's friend Dr. Sovac attends to both men, and when Cannon offers him a reward for aiding his recovery, Kovac transplants part of Cannon's brain into the dying Kingsley's skull, creating a dual personality.
After Malukan immigrants engage in a string of corpse mutilations at various New York City hospitals, a doctor and a morgue assistant travel to the Maluku Islands to investigate.
An obsessed scientist conducts profane experiments in evolution, eventually establishing himself as the self-styled demigod to a race of mutated, half-human abominations.
Tampering with life and death, Henry Frankenstein pieces together salvaged body parts to bring a human monster to life; the mad scientist's dreams are shattered by his creation's violent rage as the monster awakens to a world in which he is unwelcome.
A mad scientist creates a monster called "Mosaico," who breaks out of the laboratory to hunt down and kill beautiful women.
Professor Frankenstein creates a teenager from an accident victim, who gets angry when he learns he is going to be taken apart.
When Chris and Andy order a model from an escort service, they find that something is unnaturally wrong with Natasha, something deadly wrong.
A mad scientist creates man eating creatures from carnivorous plants.
After a pawn shop robbery goes askew, two criminals take refuge at a remote farmhouse to try to let the heat die down, but find something much more menacing.
A fugitive doctor tries to raise the dead for South Sea Islanders.
Dr. Bill Cortner and his fiancée, Jan Compton, are driving to his lab when they get into a horrible car accident. Compton is decapitated. But Cortner is not fazed by this seemingly insurmountable hurdle. His expertise is in transplants, and he is excited to perform the first head transplant. Keeping Compton's head alive in his lab, Cortner plans the groundbreaking yet unorthodox surgery. First, however, he needs a body.
Murders, with victims dying from spines broken by brute strength, erupt in the city and the killers, when encountered, walk away unharmed by police bullets which strike them. A police doctor's investigation of the deaths leads to the discovery of an army of dead criminal musclemen restored to life, remotely controlled by a vengeful former crime boss and a former Nazi scientist, from the latter's laboratory hidden in the suburbs.
Dr. Henry Jekyll is a well-regarded physician whose evenings are spent researching a rare and sacred Amazonian flower so potent it's said to literally separate the soul, giving life to man's Dark Self. The obsessive experiments to isolate its psychotropic properties happen to coincide with a series of brutal murders gripping the city with fear. Jekyll knows it's no coincidence. While his nights are lost to him, he awakens with bloody mementos and violent memories of the screams of his victims.
Dr. Hohner, theatre physician at the Vienna Royal Theatre, murders his mistress, the star soprano when his jealousy drives him to the point of mad obsession. Ten years later, another young singer reminds Hohner of the late diva and his old mania kicks in. Hohner wants to prevent her from singing for anyone but him, even if it means silencing her forever.
An insane surgeon's obsession with an actress leads him to replace her wounded pianist husband's hands with the hands of a knife murderer--hands which still have the urge to throw knives.
Chaney plays two roles: mad scientist Arthur Lamb and Lamb's "experiment", known only as the Ape Man. This hideous creature was the result of Lamb's attempts to transplant animal glands into human beings. A lost film.
An unnamed doctor has always had everything he's ever wanted, but that has only made him develop more extreme and depraved needs. He kidnaps a young couple in the prime of their life together and forces them into a game of torment that slowly extinguishes their hopes for survival.
A fugitive, dangerous madman reaches an English village where he confronts his former partner who left him for dead in the jungle after their discovery of a diamond mine. When the former partner also claims to have since lost the mine and all its wealth, which he took all for himself, and though the partmer is still living in a state of luxury , the madman takes up an offer from a crazed scientist to make him invisible, something the scientist has already done with experimental animals, so that he can take revenge.
In 19th century England, a noted brain surgeon rescues a former student from being hanged on a false conviction for murder, and spirits him away to an ancient, repurposed abbey far in the countryside. There, he connives his pupil into assisting him in mapping the functions of the various parts of the human brain, using living subjects who are under a terrible animation-suspending drug called "black sleep". Subsequently, the student, along with the daughter of one of the subjects, discover that most of these subjects have survived but are being kept in a dungeon-like cellar, in various stages of physical and mental derangement...