Human space explorers arrive at a strange, desolate, alien world to investigate a transmission coming from the surface. Investigating they come across an ancient derelict spacecraft containing the skeletons of their giant crew members. One by one the human crew is killed off by a species of parasitic alien which takes over their bodies.
This is Planet of the Vampires (1965), Mario Bava's horror-science fiction hybrid. As usual, Bava extends his budget through creative sets and his stylized use of color and lighting. The space crew is decked out in mod leather outfits that look like the SS version of the X-Men costumes, and there are some interesting visuals, but as a whole, Planet of the Vampires is somewhat sluggish, padding out a story which could have been told in about half the time allotted for it. Despite the high body count and Bava's experience with horror and suspense films, this movie is not terribly suspenseful. Because of the atmospheric quality of lighting, the similar hair styles and identical uniforms it was often hard to follow who had been killed off and when exactly.
There are also no vampires per se in this movie. Disembodied aliens have been trying to lure space explorers to their dying planet for some time, using their powers to turn the visitors homicidal against one another in order for them to inhabit the dead bodies so they can take control of their spacecraft and leave the planet and take over the planet of their unwitting rescuers. So the undead are really just the dead being puppeteered by an inhabiting life form. No body bites, eats or drinks the blood of anyone else.
It's an interesting film to watch, particularly when noticing its obvious influence on Alien (1979) and it really feels like the kind of movie that would show up at 1:00 AM in the days before cable.