This Spanish/German/Italian co-production is not nearly as good as you’d hope it to be, although it has it’s points. Amusingly, the plot is not that far off from Plan 9 from Outer Space’s, although it’s not quite as close as was Invisible Invaders. Michael Rennie (!) sadly plays the lead alien.
There is a German DVD that supposedly has a very nice print of this, I would like to see that someday.