Creature features, monster movies, or however you'd like to refer to them, are old defining staples of the horror genre that were as loved in the 50s as they are today. Many of film's most memorable villains are creatures; thus, many of history's greatest horror films can be considered "creature features."

There's no boundary on what may constitute a killer creature in horror, and filmmakers are always finding fun, inventive ways of villainizing animals and objects.

There's the obvious movie monsters, like vampires, werewolves, mummies, and zombies. There's the commonly seen creatures like vicious sharks, killer crocodiles, and even deadly bugs. Then there's the laundry list of classically less threatening creatures that still leave behind carnage in B-horror history, like slugs, roaches, and bats.

While monster movies have been hot ticket items since the early days of film, genre lovers haven't tired of watching otherworldly creatures, rodents, mutants, and the like wreak havoc on screen. The 80s proved to be an important decade in the revival of the creature feature, as 50s monster madness met camp, practical effects, and high levels of gore. 80s filmmakers attempted to resurrect 50s movie magic in a new way; often while shamelessly trying to recreate more recent blockbuster smashes like Jaws and Alien, which led to an abundance of amusing creature features, ranging from surprisingly great to enjoyable crap.

One would argue the 80s brought some the finest monster movies in horror history, i.e. The Thing, An American Werewolf in London, or The Evil Dead. They also brought a lengthy list of lesser regarded efforts, some of which gained cult followings, while others fell completely through the cracks. We're looking at the latter in this list of sleeper creature features.

10 Slugs (1988)

Synopsis: Man-eating slugs terrorize a midwestern town.

Spanish Director Juan Piquer Simon blessed exploitation lovers with 1982 slasher cult classic Pieces - an especially gross, obscure slice 'n' dice flick that would go on to develop a devout following for its gruesome kills, nonsensical story, hilariously bad acting, and generic gory slasher goodness.

Years later, JP Simon followed much the same formula with Slugs. In the vein of Pieces, Slugs features a story just passable enough to work, a cast of unremarkable characters, over-the-top acting, and hilariously poor dubbing. Fortunately, like Pieces, Slugs also packs violent kills, an abundance of blood, and an enjoyably nasty tone.

Though many creature horrors/mini-monster movies began straying into sillier camp territory throughout the 80s, Slugs keeps its terror brutal and gross. The concept may sound like a stupid set-up for light kiddie horror - Killer slugs terrorizing a Midwest town - but what ensues is anything but kid-friendly (and shockingly disgusting for that matter!)

In one notable scene, a slug crawls into a gardener's glove. As he bangs his hand on a table to remove the glove, he trips over chemicals and knocks a shelf down, which falls on top of him. He resorts to sawing his hand off. His wife enters the greenhouse and sees her husband on the ground, missing a hand, in a pool of blood. She knocks a lamp over in shock, causing the entire greenhouse and their home to go up in flames.

This level of ruthlessness from Simon isn't specific to that one scene; In fact, the flick is surprisingly bloodthirsty in its entirety. It's fun, unseemly, and gory beyond belief. Don't write this off as some middle-of-the-road, mostly silly creature feature. It is silly, and not far from cinematically bad, but it's a crowd pleaser for gorehounds and too littered with kills to be dull for even a moment.

9 Humanoids From The Deep (1980)

Synopsis: Residents of a small coastal town, led by a fisherman and a scientist, fight back against half-human creatures from the sea that attack women.

A sleazy homage to monster movies of the 50s, Humanoids From The Deep follows the Roger Corman blueprint he laid in his earlier years, yet wedges in the graphic slaughter and vulgarity horror lovers would grow to expect as the 80s went on.

Humanoids From The Deep may check a lot of horror fan boxes: Weird disaster striking a coastal town, splattery fun, copious kills, plenty of nudity, and murderous fish creatures trying to mate with human women. That last one's a bonus.

The story's kept simple, as it should be with a killer creature outing, and the crew of "fishin' town" characters are fun to follow. Humanoids From The Deep is far from Corman's finest, but it's a frightening delight as far as creature features go, and more pleasingly uncanny than the norm. Fans of aquatic horror will find themselves perfectly in their element with the flick. Enjoyers of weird will too. Those lusting for blood also won't be disappointed. There's a little something for every horror fan in Humanoids From The Deep, unintentional comedy and fantastic effects included.

8 The Nest (1988)

Synopsis: Carnivorous cockroaches are overtaking a little island. A scientist, an exterminator, and the daughter of the island's mayor join together to stop them.

It's important to note off the top that The Nest is nothing to write home about - Unless whoever's in your home absolutely adores over-sized cockroaches. What starts slow eventually builds towards true nastiness, and if you stick with The Nest in the interest of grossing yourself out, you won't be let down.

The film's first act drags as we wait for The Nest's unimaginative characters to figure out what exactly is taking place. Hint: Carnivorous cockroaches are taking over a small island. Once the mystery is out of the way, however, grossness is cranked up to high-voltage. Matters kick into high gear around the third act, and The Nest becomes a captivatingly foul little number with gruesome action, beautifully repulsive practical effects on display, and a memorable conclusion.

Why The Nest stands out as impressive to me is simply this: What very well should be just a dumb bug movie is a shockingly effective and gristly low-budget man vs. nature horror. Like Slugs, described above, The Nest stuffs cruel butchery and heavy amounts of blood into a standard monster movie vehicle, making for a deliciously disgusting watch. If you're scared more by "gross" than "eerie," you may actually find some terror here, too.

7 The Terror Within (1989)

Synopsis: After an apocalyptic chemical warfare experience goes awry, 99% of the Earth's population is wiped out. Those aboveground who survived the experiment have mutated into hideous gargoyle creatures. A team of scientists beneath the earth's surface must fight for their lives and find a solution.

On the surface, The Terror Within is an entertainingly bad Alien rip-off. Beneath the surface, it's still an entertainingly bad Alien ripoff, but that's enough for some of us.

This post-apocalyptic, extraterrestrial gross-out gorefest follows a team of scientists in an underground laboratory who are tasked with fighting for their lives against sizable humanoid creatures, referred to as "gargoyles." Cheesy as these gargoyles may appear, they have a menacing quality that works, and the rubber suits aren't half-bad for a shlocky B flick.

Acting ranges from horrific to pretty bad, though you've gotta appreciate a George Kennedy role, and the script isn't any more impressive. There isn't much atmosphere to note. Surely, The Terror Within could benefit from something palpable in mood that sets it apart from the laundry list of Alien knock-offs that littered the 80s and early 90s, but where mood lacks, low-grade creature feature shlock steps in to save the day. We'll file this one under "bad but thoroughly enjoyable," with gore galore and fun monsters carrying the show.

6 The Stuff (1985)

Synopsis: A tasty goo oozing from the earth is marketed as the newest sensation in desserts, however it's turning consumers into zombies who will do anything to get more of this goo.

Larry Cohen's The Stuff actually may not fall under the umbrella of "sleeper" any longer, as it's built up quite a following in recent years thanks to the 'net. Fans of horror comedy, monster movies, and general 80s delights alike found something to love, and this title seems to be mentioned more than ever. Still, a look at 80s creature features wouldn't be complete without it.

Part satire, part silly eco-terror, full Grade B shlockfest, The Stuff takes a goofy premise like "killer yogurt" and runs with it, haphazardly in heavy shtick. Comedy outweighs horror, and how could it not when your villain is a goopy substance? The acting is atrocious in spots, the editing slows the flow a bit, and any sort of astute social message is muffled by sheer outlandishness. To that I say, great! The Stuff is pure cheese, favoring the engrossingly ridiculous over true horror. It may not have real scares or any agitating dread permeating throughout, but The Stuff does offer enough gruesome bits (helped by excellent effects work) to keep any horror hound engaged.

Between hilarious dialogue, silly kills, and nonstop madness, anyone seeking nutty monster action can't go wrong with The Stuff. Cohen has made better horror (see: It's Alive) but this flick is a true oddity that holds great value in its intentional silliness.

5 Alligator (1980)

Synopsis: A baby alligator is flushed down the toilet in Chicago. After feeding on sewer rats that have been injected with growth hormones, the reptile grows enormously, breaks out of the sewer, and rampages against the city of Chicago.

Take your Blockbuster aquatic monster masterpiece and move elsewhere, Steven Spielberg, Lewis Teague's Alligator is swimming up from the sewer.

I'll go so far as claim that Alligator has at least a watered-down version of everything that makes Jaws or Joe Dante's Piranha great: A blood-thirsty villain that draws LOTS of blood, characters who are thoughtful enough to hold our attention, and a real witty script that's loaded with funny lines. It's no Jaws, of course, and it's no Piranha, for my taste, but Alligator is about as good as films of the large crocodile variety get.

Thanks to the superb script from John Sayles, (who also wrote Piranha) this bargain-basement, sewer monster kill show is smarter than it should be. Our heroes David (Robert Forster) and Marisa (Robin Riker) are compelling characters for this sort of affair, and the two have an amusing chemistry. Acting across the board in Alligator is surprisingly great. The movie only falters in its dated effects and somewhat laughable miniatures, but for fans of cheese such shortfalls are a benefit.

If you haven't yet seen the city of Chicago terrorized by a toilet gator, Alligator is perhaps your only chance to do so (until things really hit the fan.)

4 The Deadly Spawn (1983)

Synopsis:Alien-like creatures arrive on a meteor and terrorize a small town, forcing four horror-loving teenagers to find an escape.

The Deadly Spawn is as campy as camp gets, coming across like a group of inspired teens with minimal resources decided to put together a sci-fi monster flick. And that's not terribly far off.

Made on a shoestring budget of $25,000, The Deadly Spawn pits a group of strangely intelligent (for 80s horror) teens against a horde of monsters who crashed down to earth by way of a meteor. Said monsters are effectively creepy for an almost budgetless early 80s venture. While some filmmakers go the way of bodysuits or miniatures, director Douglas McKeown and team favor the puppet route, and to successful effect. The Deadly Spawn's "creatures," or razor-tooth wormy things, have a frightfully good look.

Plot doesn't leave much to think about, though it's handled well, and there's enough neatly crafted gore to sustain viewers. As mentioned, the film's teens are bright and adept, as horror fans themselves, which marks The Deadly Spawn one of the earlier "meta horrors." Of course a sci-fi horror mess from '83 may never receive that rightful credit, but let it be known!

The term "gem" is disgustingly overused in entertainment writing these days, though it applies here. The Deadly Spawn is a gory little treasure with cool creatures and a great cast. It won't wow anybody, but it's a hoot.

3 Razorback (1984)

Synopsis: A killer boar attacks and kills several people in the Australian outback, including a journalist. Her husband vows to investigate.

Beautiful cinematography isn't ordinarily a factor in exploitation flicks, nor is it seen frequently in horror B movies, but picturesque shots are very much present throughout Russel Mulcahy's Australian creature feature Razorback. The Australian Outback lends a gorgeous, rightfully isolated setting. Let me tell you, this is wildly nightmarish and fascinatingly atmospheric for a movie about a killer pig.

While most films of the subgenre, including the ones I've written about, don't put much care into building suspense or crafting a tense feel, Mulcahy takes a slow-build approach that keeps you gripped. Razorback is eerie throughout, which is more than what could be said for almost any similar film, and bloody fun exactly when and where it's supposed to be.

Scenic views, gross hillbillies, a hilarious killer boar, and strong performances add up to fine entertainment in this gloriously gorey, sun-drenched ride.

2 The Brain (1988)

Synopsis: A psychologist/self-help guru uses an alien organism to brainwash people through their televisions.

Like my grandfather always used to say, "You can't go wrong with an ambitious 80s sci-fi horror about a brain that eats people, bitch." I don't know why he called me a bitch.

One of the great facts about Ed Hunt's The Brain is you can gauge based on plot alone whether or not it's for you. If you like the idea of a psychologist storing a killer brain in a thought-control institute, you'll pass time favorably with this one.

An imaginative creature feature that ticks all the necessary boxes, The Brain is everything a silly low-budget horror flick should be, with added strange and a potent surrealness. You won't be hiding under the covers throughout this journey, but you'll have quite a few laughs and probably end up recommending it to other 80s cheese lovers.

After one watch of The Brain, you'll never look at evil brains in gelatinous goo the same way again. You'll also be a little less trusting of self-help gurus, which is correct.

1 Leviathan (1989)

Synopsis: A group of deep-sea miners face off with a mutant creature that was the result of a genetic experiment gone horribly awry.

Leviathan borrows quite obviously from The Thing and Alien, so it can't be astoundingly original by any standard, but it's fun underwater monster mania anyway. Featuring what could be considered the all-star lineup of B-movie actor standouts, Leviathan boasts a fun cast, trite yet entertaining premise, great creature effects, and moments of exceptional body horror. In fact, all of the monsters are pretty impressive until the last one shows up, which does dampen matters a bit. Regardless, there's joy to be had between grotesque effects and fine performances, and the aura of deep sea doom is powerful enough to make a viewer feel something.

Peter Weller, Amanda Pays, Richard Crenna, and Ernie Hudson are all wonderful in their roles, and Daniel Stern's always great to see. The acting may be better than the film itself, and that's a rare accomplishment for the 80s creature feature. Whereas most actors in these sorts of flicks feel out of place or clueless, the cast of Leviathan is putting on thespian expo. That may not match the subject matter at hand, but it's all good in fun. If you've ever been curious how The Thing would play out underwater, you may be in the market for Leviathan.