5 Forgotten Sci-Fi Horror Movies That Still Hold Up Today

There's nothing like the blending of two different genres to really bring out the unique flavors of both — it's like the cinematic equivalent of mixing something salty with something sweet. In the case of horror sci-fi, it allows filmmakers to explore the darker side of technology and science, pushing these blended genres to terrifying extremes. Some of these hybrids have wound up being classics of both parent genres — consider "Alien" or "The Thing," for example. Horror? Sci-fi? Definitely both.

But others have found themselves pushed to the side, overshadowed by films that stick more doggedly to one genre or the other, rather than splitting the difference between the two. As a result, it's often a campy little subgenre that finds itself with a tendency to fly under the radar. And while none of the films on this list were knocking down Oscar's door when they were first released, they're still a lot of fun, and have held up remarkably well over the years.

Normally, when you think of vampires, they conjure up images of dusty old castles or sparkly gents with a penchant for human blood. That's not quite the case with "Planet of the Vampires," which, to be totally honest, doesn't even have any vampires in the traditional sense. Directed by Mario Bava, the Italian filmmaker known for his work in giallo horror, "Planet of the Vampires" instead features alien creatures that fall somewhere between zombies and demons. 

As two spaceships crash land on an unknown planet, things quickly grow dire for one of the ships. The aliens begin to possess some of the astronauts, turning their hosts onto the others. It's only through the formidable strength of the mind of the other ship's captain that their crewmembers survive at all.

Eerie and disturbing on a fundamental level, "Planet of the Vampires" may not have the jump scares or advanced special effects of some of its successors, but it nonetheless received praise for its inventive filmmaking style. Monthly Film Bulletin called it, "a triumph of mind over matter, or of Bava over a shoestring budget and appalling dubbed dialogue ... [Bava] does atmospheric wonders with pastel-shaded fog and cunning camerawork."

"Strange Behavior" takes the teen slasher genre that was beginning to pick up steam in the late 1970s with "Halloween" and "Black Christmas," and adds a malevolent taste of medical experimentation to its violent proceedings. In a small, quiet suburban town, members of the community have been found dead with increasing frequency. At the same time, students at the local high school are signing up to make a little extra cash as test subjects in a research facility's seemingly innocuous experiments. Coincidence? Unlikely.

Although it's clearly made on a small budget with only a few established actors among the cast (including Louise Fletcher, who had won an Oscar for her work in the Jack Nicholson classic "One Flew Over the Cuckoo's Nest" several years earlier), "Strange Behavior" is shot in a way that makes it feel genuinely tense and unsettling. The squeamish among us may even need to look away for a few moments involving needles. It's set in the United States but was filmed in New Zealand, and is now best remembered as being that country's first major foray into the horror genre.

During the 1930s and 1940s, Universal Pictures became known for their monster movies, which included "Frankenstein," "Dracula," "The Wolf Man," and "The Invisible Man," amongst others. All are pretty much stone-cold classics. So in a way, it's not the fault of "The Mad Ghoul" that it couldn't stand up in comparison to its fellow monster flicks — what movie could? Although "The Mad Ghoul" may not reach the heights of the absolute top-tier films Universal had on offer at the time, it's much more fun than it gets credit for.

For one, we love the subtler transformation sequences as the nefarious and lust-filled Dr. Morris (George Zucco) uses a chemical gas to turn Ted (David Bruce) — the man he sees as a challenger for a woman he desires — into a dead-eyed zombie slave willing to do his bidding. Its design isn't as iconic as Boris Karloff's Frankenstein, but it's effective nonetheless. There's always room for one more mad scientist in the horror sci-fi genre, and Dr. Morris proves an especially effective villain in his ceaseless efforts to win over Isabel (Evelyn Ankers), by any means necessary.

If you liked the popular '90s horror comedy "Arachnophobia," "The Nest" makes for a perfect double feature. It has a similarly dark sense of humor, using creepy crawlies to tell a horror story that never takes itself entirely seriously. Our setting is a humble New England island community that's beginning to have a major cockroach problem. But their issues are about to get a whole lot bigger — both literally and figuratively. It turns out that a biotech company has been conducting secret genetic experiments in the area, and the result is a new breed of seemingly indestructible flesh-eating cockroaches, which are now reproducing asexually and in massive numbers. (The science behind it all is, shall we say, murky.) 

To avoid a total takeover — especially considering the fact that cockroach infestations are famously difficult to get rid of under the best of circumstances — the town sheriff (Franc Luz), his estranged ex (Lisa Langlois), and a local exterminator (Steven Davies) need to team up and eradicate the titular nest with a whole bunch of explosives. "The Nest" is campy, silly, and delightful — even if its practical effects will end up making your skin crawl. It's even based on one of the best pulp novels of the '80s, also named "The Nest," and written by Eli Cantor (under the pseudonym Gregory Douglas). It's been republished recently as part of a pulp revival helmed by modern horror fave Grady Hendrix.

What if we told you that there was a '90s horror sci-fi film that starred Katie Holmes (the same year that the first season of teen sensation "Dawson's Creek" came out, turning her into a superstar) and James Marsden, and has the absolute banger "Flagpole Sitta" by Harvey Danger on its soundtrack? Well, Virginia, there is such a film — it's "Disturbing Behavior," an edgy-lite tale of a school that resorts to mind control techniques to turn its anti-social elements into fine, upstanding young achievers, with unexpectedly violent consequences. 

Although its attempts to be cool aren't always quite as successful as its filmmakers would hope, it has a strong anti-authority leaning that makes it a perfect fit for the 1990s. And while in recent years, it's been overshadowed by horror stalwart "Scream" and cult classics like "The Faculty," "Disturbing Behavior" is still plenty of fun in its own right. (Complete with an appropriately cynical alternate ending.)