The Grasslands

There's a small building somewhere in north western America, up along the border between Oregon and Washington. It's just a short, little, old shack in the woods, off the highway. Anyways, inside, there's a spiral staircase made of grating that goes straight down. If you go all the way down, you'll find yourself stepping out into an endless field of tall grass. There are many bones surrounding the bottom step of the stairs, and things move in the near distance. Nobody who has ever seen these things has come back to say what they are.