Mysterious 'rainbow angel' spotted by hiker
What you're seeing is an atmospheric-optic phenomenon known as a 'Brocken spectre' and a 'glory.'
Observing this type of phenomenon is rare because to see it, everything has to line up perfectly.
'Glories' are normally situated below the horizon and occur close to sunrise or sunset, but they're only observed at higher elevations.
In order to see one, the sun has to be behind the observer, and there has to be a layer of cloud or mist beneath them -- that works to deflect light and create a shadow.
What you're seeing in the 'glory' above is the shadow of the hiker who captured the footage.
The 'glory' is the 'rainbow' portion of the phenomenon and the 'spectre' is the shadow which, in this case, is human-shaped.
Here are some images of other Brocken spectres:
