In the town is the local beauty, Starla Grant (Banks), a schoolteacher who married the local rich guy, Grant Grant (Rooker). But, the bumbling police chief, Bill Pardy (Fillion), still carries a torch for Starla, and his unrequited love sometimes colors his judgment. One night, Starla is in curlers in bed and not in the mood, so Grant heads out to the local bar and hooks up with the local town floozy. While they're stumbling around the woods together, they spot a glowing mass that ends up shooting something out at them. They're hooked.

Over the next few days, Starla notices Grant acting a bit unusual. She also notices that dogs are disappearing in the neighborhood, and telephone poles are papered with "Lost" notices. Grant has put a lock on the door to the basement, claiming it's getting close to her birthday (four months away), and his face grows more and more contorted and pus-filled, but he dismisses it with "it's just a bee sting."

Meanwhile, the foul-mouthed mayor (Henry) is trying to figure out why weird things are going on around his town, and he berates Chief Pardy for his laziness and flies off the handle when he doesn't get his Mr. Pibb when he wants it. When they all corner Grant at a barn, they find a rather monstrous chubby lady who explodes and sends thousands of little squiggly slugs out to dive into people's mouths and take over human bodies.

The humans turn into zombies, they meld into one consciousness, they pop out of the torsos of their victims, and somehow along the way the humans discover the creatures can all be killed if the initial host is destroyed. It's up to Starla, Pardy and his band of Keystone Kops to save the world.

A gonzo drama meant for a drive-in

Not even the Scary Movie spoofs have as many references to the SF and horror classics as this film. Writer/director Gunn is an obvious fan, and his early work with Troma has taught him to borrow and steal from the best. In fact, he even borrows from his own re-imagining of Dawn of the Dead.

It's impossible to list all of the obvious film influences, but here are a few of the more obscure references that are fun to look for. Note the cameos: Lloyd Kaufman from Troma is a "Sad Drunk," Rob Zombie is the voice of Dr. Karl, and Tom Heaton, known for playing alien abductee roles, is Tourneur. In the background, look for references to favorites of Gunn (sort of like the store names in the Dawn of the Dead remake). There's Henenlotter’s Saddle Ranch, a reference to the creator of Basket Case, and the Earl Bassett Junior High School, where Starla teaches, named after Fred Ward's character in Tremors. The Max Renn Guns & Ammo shop is an obvious reference to makeup artist Maxine Rennes-Gunderson, and every time a TV set is shown in the background, Toxic Avenger is playing.

It's pretty clear from the outset that this is not a horror film to be taken seriously. But, even between the laughs, there are a few moments that will cause some jumps and a few scenes with the squiggly worms that will cause some squirming in the seats. Like an early David Cronenberg film, it's creepy and funny, horrific and hysterical, brutal and unyielding. No one is safe. Dogs are mauled, a baby is absorbed (off-camera). Little girls become zombies and turn into creatures with voices sounding a lot like Heather O'Rourke's "They're here."

A great deal of the humor comes from Rooker, who made his name in Henry: Portrait of a Serial Killer. As he transforms slowly into the creature, he constantly denies anything is wrong, with deadpan delivery. He has one of his arms grow out to stupendous proportions and has tentacles sprout out of his chest, so the police department nickname him "squid" and use paper cutouts of squids to track him on a map. The phallic-looking worms and probing tentacles that invade a woman and force their ways into people's mouths are disturbingly bizarre but best left to Gunn's therapist for interpretation. And, one can interpret the religious symbolism—with the birth in a barn of a new kind of humanity—but that may be stretching.

Banks and Fillion reveal some of their comedic talents; they are able to express concern and fear and yet able to wink at the camera, as Harrison and Carrie did so well in the early Star Wars. Fillion, of course, has had practice doing that as Malcom Reynolds in Serenity, but this is a far less heroic character for him, a bit more of a doofus, and that makes it fun.

Some of the lines, although they depend on obvious clichés, are destined to be repeated. "That looks like something that fell off my dick in the war," one old coot says while hunting the aliens. Then there's a funny scene in a car, where they discuss outhouses and toilets, that has a definite ad-lib feel to it.

If there's any real flaw in the whole thing, it's that Gunn has mish-mashed the creature into every possible monster he's ever watched. From the Borg to The Fly, from Alien to Invasion of the Body Snatchers, he's incorporated mythologies of vampires, blobs, zombies, The Thing and all sorts of other creatures so that ultimately this thing from another planet makes no sense at all. But then, if that's going to bother you, turn on the Discovery Channel.