Royoporus badius, commonly known as the black-footed polypore or black-leg, is a species of fungus in the family Polyporaceae. It causes a white rot of hardwoods and conifers. The species is found in temperate areas of Asia, Australia, Europe, and North America. It has a dark brown or reddish-brown cap that reaches a diameter of 25 cm (9.8 in), and a stipe that is often completely black or brown at the top and black at the base.