[50sDad]

Odd you should mention it, but there are a lot of impressive parallels between the phenomenon. “Dancing a a Faerie ring” was thought to produce the same “lost time” effect as a supposed alien encounter. Some experts view them as both either manifestations of the way our human psyche can delude us (internal hallucinations), or external demonic activity screened through what our limited wetware can understand.

[Rudder]

Fairy Rings, in my experience, refers to a circle of mushrooms growing, often, but not always, around cow patties. Also, these mushrooms are quite often hallucinogenic.

[PureSolace]

I think I’ll second the “external demonic activity.” :)