A giant amongst the slime moulds, Brefeldia produces a massive fruitbody (aethalium) up to 30 cm long. The young aethalium is white to off-white with the texture of semolina pudding. At maturity, the aethalium turns sooty black and is about 1.5 cm deep. The black, powdery spores are scattered when the outer crust breaks away. It is not immediately obvious, but this slime mould is related to Stemonitis. Brefeldia is widespread but not common.