This Rare Optical Sight Called 'Brocken Spectre' Occurs When Your Shadow Is Cast Upon A Cloud Opposite A strong Light Source

The phenomenon is also known as a “mountain spectre” because it most commonly occurs when an observer stands at a higher altitude on a mountain and sees their shadow cast on a cloud at a lower altitude. A Brocken spectre, on the other hand, can occur in any setting when an observer’s magnified (and seemingly enormous) shadow is cast in mid air against any type of cloud opposite a strong light source.

Furthermore, if the cloud is made up of backscattered water droplets, a glory resembling a saint's halo can be seen around the observer's head, caused by sunlight or (rarely) moonlight interacting with the droplets. The glory is made up of one or more concentric, dimmer rings that are always red on the outside and bluish in the center. The phenomenon is sometimes mistaken for a circular rainbow due to its appearance, but the latter is much larger in diameter and the result of different physical processes.bThe photograph below depicts the type of environment in which a Brocken spectre occurs (the Sun is behind the observer's head).