Dryad's Saddle; Pheasant's Back Mushroom (Polyporus squamosus).
This is a Fairy Ring of Shaggy Parasol mushrooms (Chlorophyllum rhacodes), also known as a fairy circle, elf circle, elf ring or pixie ring. It is a naturally occurring phenomenon.
Fairy Ring are also known as: Fairy Circle, Elf Circle, Elf Ring, and Pixie Ring. The mushrooms in a Fairy Ring are Thiers' lepidella (Amanita thiersii) fungi. Thiers' lepidella (Amanita thiersii) fungi, is found from Texas to Indiana in the United States.