One of the strangest creatures to inhabit the lower reaches of Hives such as Necromunda's, how they came to be there is a complete mystery; however, it is known that they inhabit the Ash Wastes beyond the walls of the Hive. In the desolation of the Underhive, they reside under the dirt and rubble that litters the floors.
Extremely sensitive to vibrations they will instinctively open their shells when disturbed, swallowing down the debris and anything else above it. The Clams will attempt to eat any living thing that enters their shell, though a person is much too big for them. Nonetheless it can be very frustrating for the victim as they become trapped by their ankle in a vice-like grip. And woe be to any unlucky Underhiver who finds themselves so trapped in an isolated region of the hive, with no one to help.