It! The Terror from Beyond Space

In 1973, Earth's second mission to Mars discovers the fate of the first expedition in a chilling manner. The single survivor, Col. Edward Carruthers (Marshall Thompson), claims his crew was killed by a Martian life form while stranded on the red planet. When a rescue team finally reaches the stricken ship, they find only one survivor, and soon discover that the creature, which had stowed away on the rescue ship, is now hunting them on their return trip to Earth.