A fairy ring, also known as fairy circle, elf circle, elf ring or pixie ring, is a naturally occurring ring or arc of mushrooms. They are found mainly in forested areas, but also appear in grasslands or rangelands. Fairy rings are detectable by sporocarps (fungal spore pods) in rings or arcs, as well as by a necrotic zone (dead grass), or a ring of dark green grass. Fungus mycelium is present in the ring or arc underneath. The rings may grow to over 10 metres (33 ft) in diameter, and they become stable over time as the fungus grows and seeks food underground.
yes, it’s freaky when you see it for the first time and you don’t know why they grow in a circle.
It’s even freakier when you discover that what you thought was a curved line of mushrooms in a garden you visit often, is just one side of a giant circle.