They Live!/Fridge

Fridge Brilliance

 * It seems strange that Frank and Nada would easily be pissed off that the Drifter would sell out. As they don't even shoot humans whether they collaborate or not.  However if you look back to the Police raid scene, you'll see the drifter being cornered by cops. We never see or hear from him again until they meet up with him. Then you have the scene where two Alien cops are offering Nada a deal that would benefit him if he doesn't try to fight them.  One could assume it's because they were first worried he got arrested or killed, until they found out he sold out.   Then you realize, the cops had to have gotten their information that the resistance was using the Shantytown from someone.  Since there were no aliens here it's safe to say that The Drifter ratted them out for money.

Fridge Horror

 * The last scene of the movie after the world is exposed to the aliens, is of a woman having sex with her boyfriend only to find he two is an alien. Four things that bring on the horror.  First the initial surprise that someone whom she liked enough to have sex with is a gross rotting mockery of human being.  Second, despite the aliens considering us as disgusting to them as they do to us; it means in the alien world, the majority would be horrified to find one of their own committing their version of beastiality and interracial relations.  Third if it's possible for them to reproduce with other species, there's the likely hood she might be pregnant with a hybrid assuming they're not wearing protection. Fourth, as a bit of a nod to the then growing AIDs epidemic, the Alien could have some kind of STD. Either human or Alien.
 * In continuation of the above, but also in other venues. The sex scene also bring to light a different horror.  If these aliens are among us. To the point where they could be in a vulnerable place like our bedroom. Then they can be almost everywhere.  They could be your husbands, wives, friends, extended family. Even your kid's babysitter.