Bane to armored adventures, geocachers, and cache owners that use the word Ferrous # in cache titles; is the dreaded rust monster.
Squat and predatory, the rust monster inhabits only dark subterranean places searching for food. Rust monsters principally feed on ferrous based metals such as iron, steel, and steel alloys (such as mithril and adamantine arms and armor). These creatures may be non-aggressive, but are both curious and utterly fearless. They are immune to both magical and psionic influence in their single-minded pursuit of metal. It can scent metal from a distance (up to 90 feet) and relentlessly pursues metal objects. Its 18" movement rate ensures that most adventures cannot outrun the rust monster. If the rust monster touches the metal with its two antennae (roll a d20 “to hit” die) it rusts or corrodes the metal, which is easily eaten and digested by the creature. Weapons striking a rust monster are affected just as if the creature’s antennae had touched them. Note that magically endowed items gain a saving throw, a 10% chance of not being affected for each plus, i.e. a +2 weapon or armor gains a 20% chance of being saved. Rust monsters will stop for a melee round to devour such items as a handful of iron spikes or a mace if a fleeing party throws them away, but they will go after ferrous metal in preference to copper, silver, etc.
