At a glance, a Sheen Leech appears much like a caterpillar except for its colouring which normally ranges from silver grey to midnight blue. This perception only holds, however, until the moment when one observes a Sheen Leech making a diet on flies and other small insects. For then its unique tongue darts out from its mouth in one quick motion, much like lizards. Rather than directly capturing insects with their tongues, however, Sheen Leeches use a sucking motion to draw insects into the lone suction cup that is located at the tip of their tongues. Besides this, the other distinct physical characteristic of a Sheen Leech is that it has a transparent outer layer of membrane-like skin.
This insect is named for its ability to remove the sheen off polished steel and leather during its mating season, which it slowly ‘leeches’ off said items through its suction cup. The sheens acquired in this way reacts with its skin membrane, producing mesmerising patterns frequently of a metallic colour but sometimes with hints of an earthy brownish colour mixed in. Such patterns are the means by which Sheen Leeches attract mating partners.
Items whose sheens have been removed by Sheen Leeches do not degrade in quality in any way as a result of the ‘leeching’. That is, a polished sword might appear lusterless after the ‘leeching’ but still retains its sharp edge and a suit of leather armour is just as durable as before.
Usage in Roleplaying
The players camp in the opens overnight and wake up to find that any of the steel/leather equipments that were previously shining had become dull overnight. What's going on?
Additional Ideas (1)
Perhaps a fresh sheen removal attracts a certain spider that will spin a web cocoon around the "leeched" equipment. Chemicals in the web interact with the leeches excretion and solidify in some kind of uber hard reaction. The web can be removed but it is left with a reddish discoloration that is now much harder than the weapon/armor was. If it is leather, it is no longer supple or bendable. Works best on bladed weapons...but hope it is already sharpened. It will never lose its sharp blade but if it was dull or nicked when wrapped, it will be impossible to sharpen as well.