It! The Terror from Beyond Space

When his crew is brutally murdered on a Mars expedition, Commander Carruthers becomes the prime suspect. Taken into custody and facing a court-martial back on Earth, he discovers that the real killer -- a grotesque, slithering monster -- has stowed aboard the earthbound ship. But the indestructible creature has already begun a harrowing in-flight rampage, knocking off the members of the crew one by one. Now, as the spaceship heads toward a panic-stricken Earth, the remaining crew must find some way to stop the unstoppable...