20 Mind-Blowing Facts You Didn't Know About South Park
14. Many Episodes Have Aliens Hidden In The Background
Aliens have been involved in the DNA of South Park since the very first episode where Cartman is abducted and probed. There's also Cancelled, which explains that Earth is actually just a reality show organized by an alien species. The series goes even further than that, though: a whole bunch of episodes have aliens hidden in the background.
Yeah, in literally dozens upon dozens of episodes, there's secretly an alien somewhere in the frame. Sometimes it's a bit obvious and the alien is just a part of a crowd, but other times, it's cleverly blended into the scenery in a way that's nearly impossible to notice unless you're really looking for it.
It's commonly said that there's one hidden in every episode, but in reality the alien just pops up in random ones rather than every single week. Still, fans have collected over 100 instances of this happening, and given how well they're hidden, there are a probably a few throughout the series nobody has even noticed yet. So get hunting!