Movies like The Alligator People

A small-town doctor learns that the population of his community is being replaced by emotionless alien duplicates.

A dangerous combination of radiation and insecticide causes the unfortunate Scott Carey to shrink, slowly but surely, until he is only a few inches tall. His home becomes a wilderness where he must survive everything from spiders living in the cellar to his beloved cat.

A meeting in a London bus with jewel thief Lady Christina takes a turn for the worse for the Doctor when the bus takes a detour to a desert-like planet, where the deadly Swarm awaits.

When a small island community becomes overrun with creeping, blobbish, tentacled monsters that liquefy and digest the bones from living creatures, the community struggles to fight back.

Aliens have landed and are hiding on Earth, but need Earth’s scientists to help them fight an inter-planetary war.

In a massive, mysterious chamber, fifty strangers awaken to find themselves trapped with no memory of how they got there. Organized in an inward-facing circle and unable to move, they quickly learn that every two minutes, one of them must die…executed by a strange device in the center of the room.

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.

After going their separate ways, Scooby-Doo, Shaggy, Velma, Daphne, and Fred reunite to investigate the ghost of Moonscar the pirate on a haunted bayou island, but it turns out the swashbuckler's spirit isn't the only creepy character on the island. The sleuths also meet up with cat creatures and zombies... and it looks like for the first time in their lives, these ghouls might actually be real.

Mary Henry ends up the sole survivor of a fatal car accident through mysterious circumstances. Trying to put the incident behind her, she moves to Utah and takes a job as a church organist. But her fresh start is interrupted by visions of a fiendish man. As the visions begin to occur more frequently, Mary finds herself drawn to the deserted carnival on the outskirts of town. The strangely alluring carnival may hold the secret to her tragic past.

Army radiation experiments awaken a subterranean monster from a fissure that feeds on energy and proceeds to terrorise a remote Scottish village. An American research scientist at a nearby nuclear plant joins with a British investigator to discover why the victims were radioactively burned and why, shortly thereafter, a series of radiation-related incidents are occurring in an ever-growing straight line away from the fissure.

The first manned expedition to Mars is invaded by an unknown life form, which stows away on the rescue ship.

After being resurrected by grave robbers, Larry Talbot searches for Dr. Frankenstein in the hopes of being cured of his lycanthropy. The mad scientist may turn out to be dead, but his monster is just waiting to be found…