Fruiting Body: 8-20 cm broad; 6-20 cm tall; skull-shaped; white to tan; smooth becoming wrinkled; skin cracking and flaking with age. Calvatia craniiformis owes its distinctive appearance to its stemlike, sterile base and its smooth to wrinkled surface. The skin will eventually slough away, exposing a powdery yellow-brown spore mass. After the spores blow away the cup-shaped sterile base remains, often over winter. The flesh is white and firm when young, becoming yellow-brown and powdery in maturity.