Creating a Brocken Spectre on Schiehallion. Brocken spectres are giant shadows cast by hillwalkers when they are positioned between the sun and distant clouds, fog, or mist. The sun projects the person's shadow onto the clouds and, through an optical illusion, magnifies it so it looks like you are a giant. In this example, you can also see the pyramid-like shadow of Schiehallion, a Munro in the South-East Highlands of Scotland. With such a distinct shape, the mountain can be easily recognised from many places in central Scotland.