Brown Mold
Brown mold is found in damp subterranean areas, such as caverns and caves. It is light to golden brown in color. Brown mold feeds by absorbing heat, even body heat; where brown mold grows, the temperature is below average. Direct sunlight or ultraviolet light kills it.
If a warm-blooded creature comes within 5 feet of a brown mold, the mold drains heat equal to 4d8 points of damage from its victim, per round. A ring of warmth provides complete protection against this attack. Brown mold grows instantly from heat. If a torch is used in its vicinity, it doubles in size; if flaming oil is used, it quadruples, and fireball-type spells cause it to grow eight-fold.
Brown mold is not fed by cold light sources (e.g., light, faerie fire). The only magic that affects it are disintegrate (which destroys it), plant-affecting magic, and cold spells. Ice storms or walls of ice cause it to go dormant for 5d6 turns. A cold wand, white dragon breath, or a cone of cold kills it. Brown mold does not affect cold-using creatures such as white dragons, winter wolves, ice toads, etc.