For the most part, you can really only meet somebody once. With that in mind, Luke and Evan never really touch on the fact that this episode of "The Scooby-Doo Show" has the title character (and frightened hound in question) first meeting one of the demons ABOVE ground. Sure, he bumps into the monster again beneath the surface, but at that point he's no longer meeting him!
Aren't you glad they decided to skim past those semantics? Instead the Scooby Dudes go deep into what these denizens of hell symbolize, as they terrorize the newly founded city of Seattle. There's also just a pinch of one-upmanship, as the two seemingly vie to see who can make the worst/best pun in this episode.