The Day Mars Invaded Earth (1963)

What's Happening: Disembodied Martians create doppelgangers of human victims
Famous For: Feels like an Outer Limits episode
Slow and meandering, this generally unknown little film is yet worth preserving because of its great conclusion. And it's not too bad along the way. After we see a robot probe destroyed on Mars, we spend much time with the scientist-hero (veteran B-movie actor Kent Taylor) and his family in a vacation villa. Viewers might be annoyed at all this family drama supplanting the science fiction, but since the family members are the only ones menaced by the invading doppelgangers, the focus on these characters is appropriate. Unlike the famous Body Snatchers, the Martian doppelgangers toy with the family members at first, and then finally confront them. Will they replace them?

Goldweber, David Elroy (2012-06-14). Claws & Saucers: Science Fiction, Horror, and Fantasy Film: A Complete Guide: 1902-1982 (Kindle Locations 17315-17325). David E. Goldweber. Kindle Edition.