Professor John Mayer (Boris Karloff) and his assistant Dr. Isabel Reed (Maura Monti) are working on a device that uses atomic energy to create a powerful ray. The last experiment they tried sent an atomic ray through the ceiling and into space. Unbeknownst to him the ray has garnered the attention of aliens from outer space. Realizing that the Earth people are too primitive to be trusted with such a weapon, the aliens land on Earth to destroy Mayer’s machine and make sure the Earthlings can never use atomic energy again.

Mayer is expecting some fellow scientists to show them his invention. Among them is Dr. Paul Rosten (Enrique Guzman). Paul is an old family friend and knows Mayer’s niece Laura (Christa Linder). Paul is welcomed by Mayer and begins to rekindle a relationship with Laura. In the village there is a serial killer named Thomas (Yerye Beirute). One of the aliens takes over the mind of Thomas and uses him to get an audience with Mayer. Thomas brings what he says is a gift from the village to Mayer. When Mayer opens the box an alien entity takes over his brain.

While the alien entity in Mayer’s brain is having trouble controlling Mayer’s will, the alien in Thomas is beginning to enjoy being a serial killer.

“Alien Terror” AKA “The Incredible Invasion” AKA “The Sinister Invasion” was released in 1971 and was directed by Juan Ibanez, Jose Luis Gonzalez de Leon and Jack Hill. It is a low budget Mexican science fiction horror hybrid film. It is the last of four films that Boris Karloff did before his death. The film was shot in Mexico except for Karloff’s scenes which were filmed in Los Angeles by director Jack Hill.

This is probably one of Karloff’s worst films and none of the bad is because of Karloff. He’s actually the only good thing about it. The combination of Jack the Ripper type killer and aliens from outer space is interesting in theory but on screen it ended up being quite strident. At least for me. Had the story been fleshed out better and had the acting been better than the hybrid might have been more Mexican camp than just plain odd. I’m usually quite fond of Mexican horror because of its incongruity but here it just didn’t blend very well. I won’t say the whole film was horrible but it didn’t have near the campy fun as other Mexican treats.

There are also some plot aspects that were a little convoluted. The story has two aliens, one is a disembodied soul and a creature of pure thought that takes over Mayer’s mind and the other has a body and wears silver lame but still takes over Thomas’ mind. At least I think they are two different entities. That part isn’t totally clear.

Unfortunately, I could only find an English dubbed copy of the film that looks like it came from a damaged VHS tape.