A group of youths have the misfortune of going camping on the prowling grounds of weird creatures that resemble hairy frisbees with teeth and tentacles, which are thrown around by a hunter from outer space.
This film has the examples of:
- Bathroom Stall Graffiti: A graffiti in men's lavatory at the gas station reads "No chance, no help, no escape", which catches Sandy's attention, and she asks Sarge who runs into her there about its meaning. He later repeats the phrase to himself as he gets more unhinged.
- Big-Bad Ensemble: The Alien, who is hunting the protagonists, and the psychotic Sarge, who thinks that the said protagonists are in cahoots with it.
- Body Snatcher: Sarge becomes convinced that Greg and Sandy are aliens in disguise, and questions them at gunpoint about the upcoming Alien Invasion that he believes is about to happen. Greg plays along with it to get a chance to escape.
- Cassandra Truth: Sarge knows about the things that are killing people, but people ignore him and think that it is just a paranoid delusion of his.
- Cat Scare: There's one of these when Greg and Sandy enter an abandoned house in the middle of nowhere.
- Chair Reveal: Sandy walks up to a spinning chair that Greg is sitting on, turns it and finds out that one of the creatures has latched itself on his face.
- Creepy Gas Station Attendant: The gas station owner Joe is a weird old man who loves hunting animals and tries to warn the kids about the disappearances (which he attributes to hunting accidents) around the lake they are headed.
- Dangerous Windows: While Sandy hides from The Alien in a shed, it tries to grab her through one of building's windows.
- Dead Star Walking: Cameron Mitchell is the first victim of The Alien.
- Final Girl: Sandy, who is the first to detect possible danger of going to the lake. She's the last of her friends left standing and the one left with the responsibility of blowing up The Alien.
- Genre Shift: Well, subgenre shift. It starts out the same as most other slasher films which were starting to get popular at the time, but it plays out like a suspenseful monster flick instead.
- Infant Immortality: The scouts whose leader is killed by the creatures get away with just a fright when their owner appear before them.
- Nothing Is Scarier: No solid explanation for why The Alien is killing people is provided, but one can only imagine a reason as the bodies pile up...
- Peekaboo Corpse: Greg and Sandy find the corpses of creatures' victims strung up to a wall when they go check the Water Department shack in the middle of nowhere.
- Plunger Detonator: Joe rigs an explosive trap inside the shack that The Alien uses to store its game, which ends on a plunger detonator. For dramatic purposes, it fails on the first push because the wirings were off.
- Returning to the Scene: Taylor rigs the water shed containing The Alien's victims with explosives with the knowledge that it would return to the scene eventually.
- Shell-Shocked Veteran: Sarge, who starts to develop a crazy militaristic streak as the action intensifies.