Basic Trope: Something mundane is mistakenly thought to be extraterrestrial.
- Played Straight: Alice thinks Bob, dropped at home from a halloween party dressed as a grey, for an alien preparing for an Alien Invasion.
- Justified:
- Aliens are real in the setting, so Alice's paranoia isn't entirely unfounded.
- Subverted: When Alice tries to yank off the "mask" nothing happens.
- Double Subverted: Because Jim superglued the mask to Bob's face. It takes a lot of lost skin and hair, but it comes off eventually, proving he is human.
- Inverted: Alice mistakes an actual alien for a guy in a costume.
- Parodied:
- Secretly, Alice is herself an an alien.
- Bob freaks out when he hears what Alice thinks... because he thinks his status as an illegal immigrant has been found out.
- Played For Horror: Alice kidnaps Bob and vivisects him. And everybody else who tries to figure out where Bob went is suspected to be a fellow alien infiltrator and given the same treatment.