Matt Parker and Trey Stone have embedded lots of running gags into their long-running Comedy Central cartoon, only one of them being that "they" kill Kenny every installment. Some sharp-eyed viewers have spotted another one: A visitor from another world is buried, somewhere, in each South Park episode.

The creators/executive producers haven't gone on the record to explain their insistence on an extraterrestrial presence in each episode—sometimes as large as a grown man, sometimes as small as a face on a dollar bill—but the evidence is hard to argue with.

We've gathered a handful of close encounters below; for much more, head over here.

(via The Daily What)