Glen Canyon, Arizona, the present day. Wayne Grey (Seann William Scott), practicing at night in the desert for his upcoming firefighter entrance exam, witnesses the impact of a meteor. The next day, biology teacher Dr. Ira Kane (David Duchovny) and geology teacher Harry Block (Orlando Jones) from Glen Canyon Community College manage to get to the meteor, which is stuck in the ground at the bottom of an underground cave. By taking a sample, they discover a slimy blue fluid coming out of the meteor.
A little later, Ira finds out that myriad single-celled life-forms dwell in the fluid, evolve at an incredible rate, even while he's watching. What first seems like a sure ticket to Sweden for the Nobel Prize soon develops into a nightmare: by evolving and adapting at that unbelievably fast rate, the aliens start spreading out, killing people, and the military -- led by General Woodman (Ted Levine), who's accompanied by epidemiologist Dr. Allison Reed (Julianne Moore) -- comes in. Now it all comes down to what Darwin so rightfully stated: Survival of the fittest...
It gave rise to a short-lived animated series, Alienators Evolution Continues. It was short-lived for good reason.
- Actor Allusion: Ira doesn't trust government types because "I know these people." In-universe, he knows because he's an ex-army colonel. However, David Duchovny's previous role as Agent Fox Mulder is a notorious Conspiracy Theorist. This is especially notable because it wasn't on purpose; the director had never seen The X-Files.
- But those making the trailer evidently did, as it's used in quite a few.
- Adaptive Ability
- Alien Invasion: Via superior adaptability.
- Apocalypse How: Class 5.
- Artistic License: Biology: Played for laughs.
- Asshole Victim: Wayne's boss, who is eaten by an alien when he is about to have sex with a woman on a golf course.
Wayne: (trying to suppress a grin) "Well, uh... that's too bad."
- Also, the shoplifting teen girl in the mall, who gets attacked by one of the pterodactyl creatures, although she survives.
- Ass Shove: They kill the ultimate alien with a shampoo enema administered via firehose. Though it sucks Harry into its ass for at least a minute before it dies.
Ira: GIMME BACK MY FRIEND, YOU BIG SPHINCTER!
Harry: IT'S HOR-R-R-RIBLE IN HERE!
- Big No: Played for comedy during the "alien extraction" scene:
Dr. Paulson: Maybe we can catch it in his colon.
Nurse Tate: How are you going in?
Dr. Paulson: (dramatically) Rectally.
Harry: (in a VERY high-pitched squeal) Nooooooo!
- Bigger Is Better: One of the organisms, in response to being napalmed, becomes a HUGE amoeba-thing. With an anus.
- Black Dude Dies First: The Trope Namer, though it is almost immediately Defied Trope.
- Bloodless Carnage: A lot of people are attacked and mauled by the evolving life-forms, with little mess to show for it. A flying raptor takes several slugs at point-blank range, and there's STILL no gore.
- Brick Joke: Near the beginning, Nadine mentions that her ambition is to be Miss Arizona. At the end, she can be seen in the background wearing a "Miss Arizona" sash.
- Call a Smeerp a Rabbit: For some reason, the lead characters refuse to call the obviously dragon/raptor-looking flying aliens that, and instead insist on calling them "birds." Maybe it's a case of Not Using the Z Word, and they're not shown to be capable of breathing fire either.
- Earlier models of the dragon/raptor actually show it to look a lot more like a featherless oviraptor. Now that would have been weird.
- Came From the Sky: How the aliens got to earth.
- Can't Get Away with Nuthin': In one scene, a shoplifter is wearing her stolen clothes under her already-worn ones. As she comes out of the dressing room, she's snatched away by the flying raptor. Once she's rescued, she vows never to shoplift again to a somewhat confused Harry.
- It's actually fortunate for her she was wearing the layers, as without them, the claws of the bird thing could have badly hurt her.
- Comedic Sociopathy: Harry vs. the alien fly.
- Creator Provincialism: Parodied (hopefully).
- Cute Clumsy Girl: Dr. Allison Reed. She trips over sand.
- And it was Julianne Moore's idea.
- Everything's Better with Monkeys: Shortly after the alien life-forms reach a simian stage of evolution, they get napalmed. And are crushed by one cell. These are the fastest and most violent things to come out of the ecosystem, in the short time they're seen before they're crushed.
- Eureka Moment: Two of these happen; one leads to the discovery that fire makes the beings grow faster, while the other leads to the discovery that selenium kills them.
- Evolutionary Levels: Played with. In fact, the later stages of the habitat spawn dinosaur-like creatures and apes. But the last creature to appear is a nigh-unkillable (well, except for the occasional enema) amoeba-like creature. This is lampshaded in the movie.
- Everything Trying to Kill You: Oddly enough averted, given the type of movie it was. When Ira and Harry go down into the underground alien world, almost none of the creatures try to harm them. There was a carnivorous tree, but really the only one to go after anyone was that big mosquito.
- Explosive Breeder
Nadine: Um, Professor, the little wiggly worm things in there are breaking.
Ira: It's not breaking, it's splitting. It's mitosis. It's how they reproduce.
Harry: No sex?
Ira: No time for sex.
- Fun T-Shirt: Allison's T-shirt with the periodic table on back leads to one of the eureka moments referenced above.
- Genre Savvy: Harry knows the black guy dies first.
- Giant Flyer: The big dragon/raptor thing that gets loose in the mall. Wayne lures it back with his skills at karaoke, which enrages it.
- Groin Attack: Wayne suffers one, courtesy of his firehose falling and hitting him right in the crotch during his exam.
- Grotesque Cute: The dog-like alien a club member finds in a house, slowly dying of asphyxiation, with a sad expression. When one of them tries to pet it, it unleashes its defense mechanism: A really ill-tempered tongue with a beak. It bites one of them on the hand before it dies.
- "Have a Nice Day" Smile: The movie poster features one of these with three eyes.
- Used for the movie's Viral Marketing, where the three-eyed smiley began appearing all over New York City in the months prior to the film's release.
- Heroes Want Redheads: Harry insists this of Ira. It turns out to be true.
- Heroic Wannabe: Wayne, who wants desperately to be a firefighter or some other type of hero to get girls.
- Heterosexual Life Partners: Ira and Harry, though Ira does get the girl in the end.
- Hey, It's That Guy!: Dan Aykroyd stars as the governor.
- Hidden Depths: Deke and Danny.
- Hollywood Evolution: The whole point.
- Hot Scientist: Allison or, for that matter, Ira or Harry, depending on one's gender/orientation.
- Ignored Expert: Ira tries to warn Woodman that napalming the aliens may be a really bad idea. And turns out to be right.
- The Immodest Orgasm: Harry's mocking impressions of what he imagines Allison's sex noises to sound like.
- Insane Troll Logic: The heroes figure out the weakness of the nitrogen-based aliens by comparing arbitrary patterns on the Periodic Table of Elements. "Hmm, well, Arsenic is the weakness of carbon-based life-forms, and Arsenic is two down and one across from Carbon. So that means that the weakness of the nitrogen-based life-forms must also be two down and one across!" Of course, because this is a comedy film, the logic is perfectly sound.
- In a sense, it's not as crazy as it sounds -- the periodic table isn't arbitrary, its organization reflects properties of the elements in the table, so the geometric relationship between elements as displayed on the table can be relevant to their chemical relationship in reality. Of course, in this case, the conclusion is still utter nonsense.
- Instant Awesome, Just Add Dragons: The dragony Giant Flyer.
- I Will Fight Some More Forever
- Jerkass: General Woodman and his fellow army officers.
- Killer Space Monkey: ...but not for long enough to get any use from it.
- Literally comes in the form of three-eyed, no-nose, ape-like beings that are one of the last to breach the habitat seal.
- Kill It With Napalm: This ends so, so badly...
- Let Us Never Speak of This Again: After Harry's mishap with the alien sphincter, he demands that Ira tell nobody of what happened.
- Life or Limb Decision: When Harry finds himself with an alien fly burrowing into his leg, he refuses to let the doctors amputate his leg until he hears that it's headed for his testicles.
- And then they decide to Take a Third Option and remove it rectally. That poor guy.
- Mad Scientist: Ira did some very nasty things with an anthrax vaccine. Unfortunately, he tested it on people who were equipped with really large guns.
- Made of Explodium: The final alien creature, after receiving an enema of anti-dandruff shampoo.
- Miracle-Gro Monster: This is why napalm should not be used as a Kaiju attack Band-Aid.
- Nested Mouths: One creature that looks kind of like a green pig has this.
- Nuke'Em: Offered as a solution to the alien problem, but the military decides to use napalm instead. Considering what napalm eventually does to the alien lifeforms, one shudders to think what would have happened if the military had taken the nuclear option.
- Orifice Evacuation:
[Dr. Paulson is going to pull the alien bug out through Harry's rectum]
Nurse Tate: I'll get the lubricant...
Dr. Paulson: No time for lubricant!
Harry: There's ALWAYS time for lubricant!
- Our Dragons Are Different: Alien predators resembling dragons are prominently featured, though the characters prefer to call them "birds." And they reproduce by regurgitating.
- Product Placement: Head & Shoulder's dandruff-killing formula also happens to kill aliens. This is parodied after the end of the movie, where the actors do a cliched commercial with forced smiles. And Harry holding his bottle backwards.
- This was Ivan Reitman's son's idea.
- Ragtag Bunch of Misfits
- Sarcasm Failure: As the guys watch an alien give birth to a newborn--which is able to thrive in the Earth's atmosphere--all Harry Block can do is shrug and say, "Mazel Tov! It's a boy!"
- Shout-Out: Take a long look at the head of the dragony thing. It closely resembles the head of the creature from The Giant Claw.
- Also, one of the bird calls that Wayne tries is "Aww-aww, ee-ee, tukki tukki!" from George of the Jungle.
- Small Name, Big Ego: Somewhat subverted. Harry is well-aware that he's not on the same-level (scientifically) as Ira or Allison, but that doesn't stop him from milking what he does know for all it's worth.
- Smart Ball: The two guys who failed biology forever by confusing a prison cell with a biological cell? They help save the day.
- Starfish Aliens: While the latter aliens resemble dragons, apes and giant single-celled monstrosities respectively, the aliens earlier in the animated series look really odd by Earth standards. Sketches of some storyboards show even more strange aliens, including trees with metallic scales (possibly based on Earth's Lepidodendron?).
- The earlier aliens do look pretty weird, but there's some pretty weird stuff in Earth's evolutionary history too; some of the Burgess Shale critters are pretty strange in their own right.
- They're supposed to be "nitrogen-based lifeforms." As anyone with a background in chemistry could tell you, this wouldn't work.
- Sort of; nitrogen-based life-forms are unlikely, but not theoretically entirely impossible.
- Those Two Guys: Deke and Danny.
- Troperiffic: The movie borrows tropes from any number of cheesy 1950s sci-fi films.
- Weaksauce Weakness: Shampoo.
- What Could Have Been: The film was originally pitched as a serious drama to Columbia and DreamWorks; but when Ivan Reitman came on board, he had different ideas.
- According to some design sketches, the final form of the alien's evolution would've been a much more humanoid form. However, seeing how difficult about how to make this a realistic threat, they decided with the giant cell.
- X Meets Y: One critic even said the film is "Ghostbusters meets Men in Black."
- You Don't Want to Die a Virgin, Do You?: A girl holding an "I can't die as a virgin" sign can be seen during the Arizona evacuation party.