Tarnisher

Tarnishers can sense magnetic fields and magnetic substances. They mostly use this ability to detect iron or other metals to eat. A side-effect of this ability is a very good sense of direction; however, they become bewildered in the presence of strong magnetic disturbances. They have been known to accidentally swarm in wild magic zones, where their polarity is thrown wildly off course.

Because their ability to corrode metal is limited, tarnishers prefer to eat smaller objects; while a rust monster might gorge itself on an anvil or a suit of plate mail, a tarnisher will generally deem that more trouble than it’s worth. Even so, tarnishers enjoy stockpiling as much iron as they can to eat later. A tarnisher den may be piled with scrap that can feed its inhabitants for years. No matter how much they have in reserve, however, tarnishers never stop gathering more.

Tarnishers gather in cities where artisans produce and discard large quantities of digestible iron objects such as nails. Smaller, friendlier, and less ravenous than their cousins, these creatures have an easier time coexisting with humanoids. Some people even find them charming, and enjoy a tarnisher’s enthusiasm for a snack of scrap metal. Tarnishers raised from hatchlings can be kept as pets, and even feral ones are friendly to anyone who feeds them. With a bag of ball bearings, one can pass a pleasant afternoon in a back alley feeding the neighborhood tarnishers.