Foulfungus is a form of poisonous mushroom that manifests as a yellow powder. If inhaled in sufficient quantities, the spores can prove toxic. Goblins are especially susceptible to foulfungus, and can die from overexposure. Symptoms include fever, sweating, headaches, vomiting, sneezing, coughing, fatigue, diarrhoea and a host of other bad stuff.

As a result of his constant visits to the ledger rooms in the rat farms, which contained foulfungus spores, Dragomir gradually became immune to the effects. He spread the yellow powder to the rest of the castle whenever returning to his duties, however, and single-handedly incapacitated most of Castle __________ for several weeks.