So...
in 2008 I was walking down a foyer in Finland (ground floor foyer of the Jyväskylä Institute of Applied Automation Technology) and a lecturer who I know walks in front of me walking the same way. He just happened to be there as I was walking in. Suddenly, a halo (a circular ring) of light appears above his head, appearing to float about 4 cm above his head, as bright as the filament in an incandescent light bulb but about 2.5 cm in height, with a circular cross section and with sub-vortices of light whirling within it and with edges and centre of more diffuse and weaker light. This lecturer proceeded to walk into an elevator, with this halo present and as the doors of the elevator closed, whatever this light was couldn't go through the solid steel doors, and the light winked out to a point and then disappeared as the steel elevator doors completely closed blocking my view.
I didn't see anything unusual about this lecturer's hair or head during this incident (other than the ring of what looked like lightning). I didn't hear any crackling or noise emanating from his hair when this appeared, nor did I see anything else unusual about his person. As far as I know he doesn't perform on any magician's or illusionist's circuit (or show) of any kind.
I questioned a few people afterwards if they had seen anything unusual about the lecturers or anything else in that building during their lectures being careful not to mention anything specific, including those students who had seen this lecturer at some point. They said they hadn't seen anything unusual. I directly asked the lecturer who worked in the same cubicle as the person above whose head this halo appeared if he had ever seen anything unusual about this person, or anything else unusual in the building, and he replied "no".
The entire atmosphere of the place was subdued, the students seemed grumpy and talked little.
Can't explain this, even now. Never seen anything like it anywhere, ever.
Really threw me off.