In the near future, a space station around Earthdetects that a gigantic asteroid is going to hit the planet. Astronauts land on it to plant bombs and detect that there's this weird slime growing all over the place. The slime hitches on one of their spacesuits and when put through the radioactive decontamination transforms into a one-eye tentacled monster that kills with electricity. When they shoot it the blood forms new creatures, so soon there are dozens of the horrible monsters.
The main characters are Commander Jack Rankin and Commander Vince Elliott (Richard Jaeckel of GRIZZLY), who are in love with the same redhead, Dr. Lisa Benson. She had left Rankin for Elliott, though she still has feelings for the former. This makes Elliott jealous and somewhat suicidal, as he takes all these chances to rid the station of the creatures.
I always found this to be a surreal horror movie. On one hand the effects, particularly the space station and astronauts in space, are fake-looking, like in a child's show, but the grimness of the situation and sheer amount of death counteracts this to some degree. It's a great example of a DRIVE-IN horror movie from the 60's.