Edward L. Cahn

In 1973, the first manned expedition to Mars is marooned; by the time a rescue mission arrives, there is only one survivor: the leader, Col. Edward Carruthers, who appears to have murdered the others! According to Carruthers, an unknown life form killed his comrades during a sandstorm. But the skeptical rescuers little suspect that "it" has stowed away for the voyage back to Earth...

Aliens, contacting scientist Adam Penner, inform him that they have been on the moon for twenty thousand years, undetected due to their invisibility, and have now decided to annihilate humanity unless all the nations of earth surrender immediately. Sequestered in an impregnable laboratory trying to find the aliens' weakness, Penner, his daughter, a no-nonsense army major and a squeamish scientist are attacked from outside by the aliens, who have occupied the bodies of the recently deceased.

A teenage couple making out in the woods accidentally runs over an alien creature with their car. The creature's hand falls off, but it comes alive, and, with an eye growing out of it, begins to stalk the teens. Meanwhile, Joe the town drunk wants to store the body in his refrigerator, but some of the alien's buddies inject alcohol into his system, and Joe dies of an overdose.