Warning: This post will contain spoilers, because they're the interesting parts.
The Last Man on Earth is about just that. After a terrible disease plagues the entire earth, Vincent Price is the last man standing, having gained immunity to the terrible disease through a bat bite years earlier. So for three years he lives alone, fending off the zombie-vampires that the disease has created. This film wasn't particularly scary (and I'm a jumpy one), but if you enjoy watching Vincent Price talk to himself, it's definitely the movie for you!
That brings us to The Fly. Basically the perfect 50's horror film, The Fly offers up screaming women, sexist children, scientist men, big machines that make futuristic noises, and insects.
Half the film is presented in flashback form as Helene Delambre tries to explain to her brother-in-law (Vincent Price, who's conveniently in love with her) and the inspector why she killed her husband. He turned into a fly, that's why. He got a little over-zealous with his "matter transporting" equipment and some of his "matter" gets a little mixed up. Now he's got a fly head and hand and somewhere out there buzzing around is a white-headed fly-man.
The second half of the film involves Vincent Price searching high and low for the white-headed fly that will prove Helene's insane story and get her off the hook for her husband's murder. His search finally leads him and the inspector to a spider web where a tiny little fly-man, yelling "help me!" a million times in a little fly voice, is about to get eaten by a spider.
This is the point in the movie at which the entire group at my house screamed. For an excessively long time. I can't really explain this scream and why it went on for so long. After all, this is a not-so-scary 50's horror movie. But seeing a fly-man get eaten by a spider is slightly disturbing. Plus, the special effects were basically horrific. So the scream went on for some time, laughing, screaming, confusion, general noise. It was exciting and an old movie night first. I'm not sure what to make of it.
But after all the screaming stopped and we calmed down, emotions were mixed. The premise was disturbing. But there were some sweet, touching moments like when the man-fly wrote "love you" to his wife on the chalkboard before getting squashed to death like any fly should. And who couldn't be happy when Vincent finally ends up with Helene whom he loved all along now that his sexy, smart fly-brother is squashed? And how can you not be appalled at their dumb little sexist son, spouting zingers like, "you know how women are"? This movie has it all. We laughed, we cried, we cringed, and we screamed.