Monstrosity (1963)

Also Known As: The Atomic Brain
Starring: Xerxes
Directed by: Joseph Mascelli

This review contains a Kitty Carnage Warning!

Cat Out of the Bag Alert! This review contains some spoilers for this film!

Synopsis: An elderly woman named Mrs. March (Marjorie Eaton) is depending on a mad scientist named Dr. Frank (Frank Gerstle) to keep her young by transplanting her brain into the body of a beautiful young woman.

Featured Feline: A black cat (played by impromptu cat actor Xerxes) lives in the mansion and is first seen eating some food in Mrs. March’s room.

Monstrosity - The Atomic Brain - black cat Xerxes eating food from plate on floor

A man named Victor (Frank Fowler) comes in and carries the cat out.

Monstrosity - The Atomic Brain - Victor Frank Fowler carrying black cat Xerxes out of room past Mrs. March Marjorie Eaton

Mrs. March employs some housekeepers with no close attachments to work at her mansion, hoping to find among these the perfect vessel for her brain. Nina (Erika Peters), Bea (Judy Bamber) and Anita (Lisa Lang) arrive on the same day. Just before they come in, the cat is seen walking down the stairs.

Monstrosity - The Atomic Brain - black cat Xerxes walking down stairs

Later Dr. Frank is seen holding the cat in the basement laboratory. He hears Nina and Bea snooping around but sees nothing, so carries the cat back into the lab.

Monstrosity - The Atomic Brain - Dr. Frank Gerstle holding black cat Xerxes

Monstrosity - The Atomic Brain - Dr. Frank Gerstle holding black cat Xerxes in lab

Kitty Carnage Warning! Unfortunately the cat is to be the test subject for the brain transplant. The kitty brain is placed into the body of Anita, who then runs around acting like a cat, much to everyone’s confusion.

When it comes time for Dr. Frank to transplant Mrs. March’s brain into Nina’s body, he decides he’d rather keep Nina for himself and transplants Mrs. March’s brain into the body of the cat. Mrs. March is less than pleased about this when she realizes what has happened and scratches Dr. Frank’s hand.

Monstrosity - The Atomic Brain - black cat Xerxes about to scratch hand

Revenge is sweet, though, and Xerxes the cat is given a chance to do some real acting as Mrs. March who takes advantage of Dr. Frank entering his atomic chamber by locking him in and flipping the switch, frying the man alive.

Monstrosity - The Atomic Brain - black cat Xerxes on atomic chamber control panel

Monstrosity - The Atomic Brain - black cat Xerxes looking through round window into atomic chamber

Monstrosity - The Atomic Brain - black cat Xerxes looking through round window into atomic chamber at Dr. Frank Gerstle animated gif

Monstrosity - The Atomic Brain - black cat Xerxes pressing button on atomic chamber control panel

Monstrosity - The Atomic Brain - black cat Xerxes pressing button on atomic chamber control panel and frying Dr. Frank Gerstle animated gif

The film concludes with the mansion burning down and Nina running away. But the narrator explains that Mrs. March wasn’t going to let Nina get away so easily and as such the black cat is seen in some insert shots, supposedly following the girl.

Monstrosity - The Atomic Brain - black cat Xerxes sitting on wall

Monstrosity - The Atomic Brain - black cat Xerxes walking

Monstrosity - The Atomic Brain - close up of black cat Xerxes

The cat is such a pivotal part of the plot that it was featured in artwork in both the credits of the film and the movie’s posters. According to IMDb, Xerxes the cat was owned by actress Judy Bamber.