Fungi, also known as moulds, grow in damp, warm, and usually dark conditions, such as underground complexes, mines, tunnels, and long-deserted buildings. Not all moulds are dangerous; most are fairly innocuous and just grow on walls or rotting vegetation, harming no one and doing a useful job of decomposing dead organic matter. Some moulds, however, can have unpleasant effects upon adventurers and other living things. Moulds are impervious to all forms of attack except fire and, given that they tend to grow in the dampest of areas, it is not always easy to burn through them.