This 200 foot-high granite and sand island is named for the challenge it presents to the OHV enthusiast. It is actually an ancient decomposing mountaintop. A dark coat of desert varnish covers the rocks as a result of exposure to sunlight. The hill is said to be haunted from old mineshafts found in the hill. This is a great off-road climbing training area for all levels of skill. From gentle sloping sand dunes on it's south side to the mixed terrain, vertical climbs, which get progressively tougher as you move north up the hill.