On one side, their carapace felt like a smooth, hard, cold, metal coin. On the reverse, they had two rows of legs that surrounded a mouth that opened and closed like an iris of razor-sharp teeth. The legs were able to retract flush to the body, completing the imitation of a coin.

Attached to the body was a flexible, segmented stinger that could be up to one foot (thirty centimeters) long that normally resided in the Ethereal plane where it was invisible to those on the Prime. Other parts of the creature that generally stayed in the Ethereal were its venom sacks and its food storage and digestive system.

Behavior

Lock lurkers were more intelligent than dogs or cats but had no known language. If summoned by a priest of Waukeen, they could be given simple instructions that they were bound to follow. Non-summoned lurkers usually needed enticement or to be given a task that was compatible with their nature and their desires.

Lock lurkers were hermaphroditic (both male and female). They were solitary creatures, so when two adults met, they would mate, but then go their separate ways. In 30 to 120 days, both adults would produce an egg sac holding a dozen to over a hundred eggs, over half of them viable, and the remainder were a food source for the hatchlings. Sometime in the following days, but no later than about four ten days, the eggs that were still viable hatched and the young consumed the unhatched eggs, and occasionally each other, until they were able to walk away and fend for themselves. Once this initial cannibalistic phase ended, lurkers never attacked each other. Lurkers matured within two to seven years.

Combat

A lock lurker's bite was just strong enough to penetrate hair, hide, skin, or leather armor for minimal damage. The stinger's lightning-fast attack could penetrate any armor and delivered a much more powerful jab that stunned small creatures (less than man-sized) for a minute or two, and injected a venom into the bloodstream that slowed all non-immune creatures for the next minute while it spread through the body. At this point, the victim had a chance to resist the poison and, if successful, was slowed for another minute as the body purged the poison from the bloodstream. If unsuccessful, the victim immediately became paralyzed in a muscle-locking rigor that lasted from one to six hours. During this paralysis, any attempt to move limbs or extremities was very likely to harm the victim further. When the poison finally wore off, the victim felt slow for another minute or two, and then completely recovered.

Lurkers patiently waited for their victims to come near enough to strike. They had exceptional vision including infravision out to sixty feet (nineteen meters) and easily blended in with other coins or hid inside boots, drawers, or chests, under pillows, or on the other side of keyholes. Their stingers stayed on the Ethereal plane except at the moment of attack, or if they were somehow forced to fully materialize on the Prime. The venom was equally effective on either plane. A lurker could transition any part of its body to the Ethereal, but never all of it at once, and it could be attacked on the Ethereal plane. It was especially vulnerable on the Ethereal during a full transition to the Prime. Lurkers slowly regenerated lost limbs or bodily injuries.

Lock lurkers carried enough venom to sting effectively over forty times per day.

Ecology

Lurkers in the wild preferred urban areas where they could prey on small vermin like insect and rodents, slowly moving to new hunting grounds as needed. They were able to withstand hot and cold environments, like the heat near an oven or in a smokehouse, or the cold of an icehouse. They were usually set to guard something, but it was unknown how loyal non-summoned lurkers were to their task. If there was no food nearby, they might be forced to leave their post to avoid starvation, for example.

Lock lurkers were valued for their venom because it was used in making potions and scroll inks for items that created slow effects. The venom was a clear, viscous fluid that had an odor like seaweed. A flask of lurker venom could fetch ten gold pieces at knowledgeable alchemy vendors. A lurker carcass was a preferred ingredient for creating the oil of etherealness and was priced from two to six gold pieces depending on how intact the body was, and if the stinger was included. And finally, a lurker egg sac with viable eggs was worth about twenty-five gold pieces in the marketplace.