A fairy ring is a circular fungal growth, often concealed beneath other vegetation except when the mushrooms grow up after a rain. Though natural in origin, fairy rings have some supernatural characteristics as well.
Normally, a fairy ring appears as just a circle on the ground. Sometimes it may not even be visible, obscured by surrounding vegetation, though nothing grows on the ring itself.
When in bloom, however, mushrooms spring up all around the ring. In darkness, these mushrooms give off a soft glow, somewhat illuminating the interior of the ring; none of the light falls outside the ring, however.
Some fairy rings encircle a large tree, often a hawthorne, though almost any type of tree is possible. Others grow far from any tree, out in meadows or grassy plains. There are many different types of mushrooms that can form fairy rings.
Fairy rings can vary greatly in size. A typical ring is around eight to ten metres in diameter, but rings as large as six hundred metres are known, and smaller ones are possible too.
A fairy ring in full bloom is a point of contact between the Shadow Realm, where the fae dwell, and the real world. This contact, like a hole in the Veil, means that the properties of the Shadow Realm and the real world mix together at that location. Though time does not become fully untethered as it would in the Shadow Realm, it no longer progresses forward smoothly. Once inside the ring, it can become difficult to leave due to a sort of suction at the border. This applies to people originating from either realm.
The effect of a fairy ring is alleviated when the leylines are at their peak around May 1. At this time, it’s possible to use the fairy ring as a simple portal to the Shadow Realm, which is not accessible by other means during peak period. Though the fairy ring is still difficult to exit, time flows normally and it’s possible to simply wait for the effect to fade, after which you’ll remain in the real world.
On the other hand, when the leylines are at their ebb around October 31, a fairy ring’s effect is amplified. The interior of the ring becomes effectively part of the Shadow Realm, and whoever steps inside will almost certainly end up lost inside the Shadow Realm once the fairy ring’s effect fades away.
Between this times, that is, during the summer, early spring, or late autumn, a fairy ring will most likely merely steal away a few hours or days of someone’s time if they venture within. Fairy rings do not bloom during the winter in temperate climates, though they may bloom at any time of year in warmer places.
Fairy rings get their name from the fact that many types of fae enjoy dancing in them. The most notable dancers of the fairy rings are the pixies, though a number of the little people type of fae also enjoy it, such as the leprechauns. In northern Europe, you can sometimes catch trolls dancing in a fairy ring. Outside of Europe, the dancing is not so common, though it does occur sometimes.