This optical phenomenon, appearing on misty mountainsides, is called...
Side rainbow
Halo
Brocken spectre
Sun Dogs
A Brocken spectre  or mountain spectre, is the apparently enormous and magnified shadow of an observer, cast upon the surfaces of clouds opposite the sun. The head of the figure is often surrounded by the glowing halo-like rings of a glory—rings of coloured light that appear directly opposite the sun when sunlight meets a cloud of uniformly-sized water droplets. The phenomenon can appear on any misty mountainside or cloud bank.
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Side rainbow
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