Aliens in Cardiff: Lampshaded and justified. When one character claims that it would be absurd for aliens to secretly invade via a High School in a small town and brainwash the population, another Genre Savvy character points out that this would attract a lot less attention than attacking a big city, which the whole world will notice. See the page quote.
And Some Other Stuff: Zeke's drugs are made from a mixture of "caffeine pills and some other household shit."
Billing Displacement: R&B star Usher is featured prominently on the poster despite appearing in only five minutes of the movie. None of the other cast members were all that famous (at the time), while Usher is, well, Usher.
Body Horror: The parasite dehydrates the old Mrs. Brummel to the point where her skin falls off of her body.
Also, Marybeth's transformation into her alien form.
Book Dumb / Brilliant but Lazy: Zeke is clearly very smart and resourceful, yet he's repeating his senior year because, instead of focusing on school, he chooses to concentrate on pursuits such as manufacturing drugs and dealing various illegal merchandise to other students.
Break Them by Talking: Used multiple times by the pod people against the heroes, but the big one is delivered by Marybeth. When she confronts Casey in the locker room, she tries to convince him that, by joining the aliens, he will be happy and will no longer have to suffer through humiliation at the hands of his peers. When Casey refuses to be swayed, Marybeth simply gives up, tells him that it's too late and that the aliens have already won, and comes after him.
Brick Joke: During the credits, clips from the movie are used to accompany all of the lead actors except for Jon Stewart. He's shown teaching again, only with an eye patch and his hand bandaged.
The Cameo: By Ain't It Cool News' Harry Knowles, of all people.
Clark Kenting: The popular girl Delilah, in order to avoid being recognized by the aliens (who are targeting the most popular kids in school so that they can infect the most people), briefly disguises herself as a nerd by putting on Nerd Glasses. It works about as well as you would expect it to work — she gets infected anyway.
Closet Shuffle: While breaking into the teacher's lounge looking for a scoop, Casey and Delilah hide in a broom closet when they hear teachers approaching. Here, they find the dead body of Mrs. Brummel and witness the school nurse get held down and infected.
Drugs Are Bad: Inverted. The alien parasites are dried out and ultimately killed by the meth-like drug that Zeke makes and then sells in the parking lot. This drug is used in order to test who has been infected with the parasite.
Dumb Muscle: Stan, much to his dismay. He feels that his heavy involvement as the captain of the football team is damaging his academic performance, and that his teachers are giving him preferential treatment just because he's a star athlete. This causes him to quit the team in order to focus on schoolwork.
Evil Overlooker: Marybeth's face at the back of the poster certainly qualifies.
Evil Teacher: The teachers are the first people to get infected, and spread it from there.
Eye Scream: Mr. Furlong gets stabbed in the eye by Zeke with one of his drug pens.
Fake American: Canadian actress Laura Harris as the Southern girl Marybeth, complete with a ridiculously over-the-top Southern accent. In-Universe, this also applies to Marybeth herself, making it a justified example.
Fake-Out Make-Out: Subverted. While breaking into the school's storeroom to steal ingredients for his drugs, Zeke cites the trope to reassure Marybeth should they be caught. However, the two aren't patient and start making out regardless.
Fingore: Mr. Furlong is bitten by the alien specimen that Casey finds. It takes a nice chuck out of his pointer finger. Later, after having been infected by the aliens, he has all four fingers of one hand cut off by a paper slicer.
Five-Man Band: Not the variety used on this site, but the one used in The Breakfast Club — the princess (Delilah), the criminal (Zeke), the brain (Casey), the athlete (Stan) and the basket case (Stokely). There's also the new girl (Marybeth) who turns out to be the Big Bad.
Glamour Failure: In addition to the obvious lack of emotion characteristic of Puppeteer Parasites, people infected with the alien parasite can be discerned by their need to drink lots of water, as the things quickly dehydrate their hosts. This is also why Zeke's drugs are so effective against them (the drugs absorb water and dehydrate people).
When Zeke is selling pens full of drugs to some students, he tells them that the stuff is "guaranteed to jack you up." Casey later repeats this line before he stabs and kills Marybeth with one of these pens.
While snooping in the teachers' lounge, Casey tells Delilah that she can be "pretty cool sometimes" (i.e. when she's not being the Alpha Bitch). Delilah asks if he's hitting on her. At the end of the film, Delilah repeats this line to Casey, whom she is now dating.
It Was Here, I Swear: Casey ends up in this situation when he brings the police to the school to recover Mrs. Brummel's body. When they open the closet, the body has disappeared and been replaced with a Resuscitation Annie Doll.
Lens Flare Censor: In reverse. The darkness is used to cover up Marybeth's naughty bits. It doesn't work so well on the DVD, though.
Lovable Jock: Stan, especially when compared to the more jerkish football players.
The Mole: Played straight when Delilah gets infected. Slightly subverted with Marybeth who, unlike most Moles, isn't working for the bad guys—she's their leader.
No Ontological Inertia: Justified. After Zeke examines one of the parasites, he notices that it doesn't have all the necessary organs to sustain itself independently and concludes (correctly) that there must be an alien queen with a telepathic link to all of her "offspring." Killing her would kill all the parasites, returning everyone to their normal selves.
Not Now, Kiddo: Even though the alien-controlled teachers make up a cover story for what he saw that would still realistically scare a teenager, Casey's parents decide he needs counseling, search his room for drugs and decide to take away his phone, internet, stereo and even his Porn Stash (which they seem bizarrely completely okay with). Because that's parenting.
Now or Never Kiss: A mild example. Stan and Stokely kiss before Stan goes out to see if the people outside are still infected, with Stokely remarking that she didn't want to have never done that.
Screw the Rules, I Have Connections!: Stan's teachers curve his grades because he's the captain of the football team. Unlike most examples, he's fairly dismayed by this, enough so that he quits the team.
The Shadow Knows: Around the end of the film, the Hive Queen tries to appeal to Casey, using the Marybeth disguise she's been using for the whole film. The shadow in the room, however, is a tentacled mass that keeps moving and nearly covers it, all coming from a average-sized teenager.
Single-Biome Planet: The head alien is from a planet covered entirely with water. This is the reason why people infected with the alien parasite need to drink lots of water—the thing needs a lot of it, and it dehydrates people rather quickly.
Sorry, I'm Gay: Stokely pretends to be a lesbian in order to prevent guys from hitting on her.
Stunt Casting: R&B star Usher in a small role as one of Stan's fellow football players.
Sucky School: There is a scene early on that takes place at a faculty meeting, where they are deciding how to divide the school's budget. Much to the teachers' chagrin, money that could be used for buying new textbooks or putting on a School Play other than Our Townnote A play that is traditionally staged without a set of any kind, and as few props as possible. Theater geeks will get a chuckle from this. is instead directed towards the football team because, as Principal Drake explains, they live in a football town. She doesn't think the football team deserves all the attention and funding, but it's what the parents want.
Also, take a look at the map of Europe in the history classroom. Despite the film being set in 1998, the map still shows a united Soviet Union, Yugoslavia and Czechoslovakia, implying that it's at least ten years old — and judging by the condition it's in, probably older.
Several of the door frames look like they could use, at a minimum, a new coat of paint.
Teacher/Student Romance: The infected Miss Burke hides in the back of Zeke's car, then attempts to seduce him when he's speeding away from the infected football team. Zeke then slams the car into a school bus, sending her through the windshield and decapitating her. She gets better. The final scenes imply that they Hooked Up Afterwards, which is at least marginally less squicky because he's been held back and is, presumably, of age.