The Ninth World
The Black Mountain
At the start of The Whispering Mountain adventure, the party encounters a black, twisted, two-tipped mountain, perhaps the eponymous Whispering Mountain. The mountain plagues their dreams with feelings of fear but also longing. It seems that others in the area also suffer from the same dreams.
When stopping in Harker's Ferry, the party asks Old Fedrick about the mountain. The townspeople react with quiet apprehension, but listen to his story. He describes an ancient mountain matching this description which once was an unnamed creature's lair, holding untold treasure. One day, a visitor from another world appeared atop the mountain and engaged the creature in battle, killing both the creature and the visitor and leaving the fortune unclaimed.
The mountain only appears in any given place for a short time. Fedrick's friend, Lothar the Shiv, once encountered it but was too scared to approach it. The rumor is that the mountain appears in a new location every 20 years.