Genea harknessii

Genea harknessii, commonly known as the dark geode truffle, is a species of fungus in the genus Genea. The species was described by Helen Gilkey in 1916.
The mature fruit is up to across. It has a convoluted, coral-like appearance. The exterior is dark brown with a hollow interior, the surfaced of which is dark brownish. The sterile flesh between the dark interior and exterior 'skin' is white to grayish.
G. harknessii grows underground in forests, especially white oak forests, but also coniferous woods. Although pigs hunt it, its edibility to humans is unknown.