An ignorant or stupid person but arrogantenough to believe if they haven't seen it or heard of it, it doesn't exist.
The guys I work with grew up in the same 50 mile area, moving from out of state and being exposed to many cultures and diversity, I was floored when the arrignoramuses thought I was crazy when I said "pomegranate". I learned that these mythical fruits simply do not exist.
A Shackteau is a humble, weather-beaten, structurally questionable shelter located in a spectacular or highly coveted place—Wales, Jackson Hole, Sun Valley, Crested Butte, coastal Maine, the Alps—where the building itself may be worth almost nothing, but the dirt, view, access, and mythology make it absurdly valuable.
In use:
Shackteâu - We thought it was an abandoned shed until the realtor called it a rare alpine Shackteâu with unobstructed views and listed it for $2 million.