Without Warning is a 1980 science fiction/horror film starring Jack Palance, Martin Landau and David Caruso. Cameron Mitchell is in this, too, and I have a soft spot in my heart for him because I loved his character on The High Chaparral. It also has Larry Storch (from F Troop).
Youtube has it online divided into separate sections. Part 1:
part 2, part 3, part 4, part 5, part 6, part 7, part 8, part 9, part 10
I watched the first 3 segments.
The New York Times says it's derivative and calls it a "wretched film." Nobody else cares much, it seems. The TCM page doesn't even have a basic synopsis.