Movies this one stole from...
V, Alien, Rosemary's baby
Seemed like a rip off of British SF classic The Quatermass Experiment (1953)
shareMidwich Cuckoos
shareThe 2 creepy twins reminded me right away of Village of the Damned.
"I'm a star. I am a big bright shining star. Yeah, that's right."
The Invasion of the Body Snatchers (grandfather of the genre) and The Hidden.
shareI would say the Quatermass Experiment and Rosemary's Baby, I don't know how Alien or V figures in here.
Walking through the cow pasture of life you are bound to step in some truth
I Married a Monster from Outer Space
shareHere is another one Protheus based on Dean Koontz
shareI'm surprised no one has mentioned the Twilight Zone episode The Parallel. I bet if it wasn't for that episode, this movie would not have been made. Of course almost every TZ episode has been adapted into a movie.
shareI'm watching this episode of Twilight Zone right now. It's similar to The Astronaut's Wife, but IMHO, it's more similar to Journey to the Far Side of the Sun http://www.imdb.com/title/tt0064519/
Edit-
This episode (The Parallel) was quite different than most TZ episodes I've seen. Not only was this one not available on Netflix or Amazon streaming (I had to download it off the torrent) but it had a "happy" ending. I thought I seen all the TZ episodes, but I guess not. Thanks for mentioning this.
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Every person that served can be called a veteran, but not every veteran can be called a Marine.