Invaders From Mars.

Youngster David MacLean sees a large flying saucer descend and disappear into the sandpit behind his home. Young David soon begins to realize something is very wrong: he notices certain townsfolk are acting in exactly the same way. With the help of local astronomer Dr. Stuart Kelston and Dr. Pat Blake, David soon realizes the flying sucer is likely the vanguard of an invasion from the planet Mars, now in close orbital proximity to Earth.