Meta: The Aliens in Cardiff Trope in Supernatural

tvrealm had a challenge where we were to explore TV Tropes either by show or by trope. They foolishly allowed meta, so I am doing that! Since Supernatural is tending to occupy my wheelhouse lately, I'm meta-ing about tropes found on the show.

Aliens in Cardiff

Looking for a place to set the disaster of the week/alien invasion/supervillain's base/origin of the bad guys etc? . . . Have the center of the plot be in an actual place, but some relatively harmless semi-known non-exotic location which makes you ask "Why THERE, of all places?" Or in the case of Supernatural, have it take place in some completely unknown non-exotic location... for example, Gleason, WI.

( Are you sure that's a real place? )