A stercorulus is a roach created through alchemical arts, specifically alchemical arts that capture brown msawhat. The chemical recipe for creating a stercorulus involves the maker's sperm or menstruation, but varies by maker otherwise. Those who do not produce sperm or menstruation can sometimes use that of another, but it requires much more msawhat.

Stercoruli are living, functional living people, but they do not have souls and cannot reproduce (these two things are not related). They usually stand about 4" long. The esoteric process to create them leaves them with residual esoteric powers and a bond to their maker.

Powers:
The powers of the stercoruli derive from the powers of the maker, but if the brown msawhat absorbs some other energies, it might have other powers. All stercoruli leave black film behind wherever they step, poisoning what they touch.

The Recipe:
First the maker must create distillation of brown msawhat, any liquid form, and infuse collected sperm or menstrual blood (forty months' worth) with it. They must then take this and put it into a rotting gourd, which they seal with wax and place at the bottom of a pond for forty days. At the end of forty days, a small roach made of smoke will be formed, which must be fed for forty weeks with rotted fruits and vegetables to become whole. Most people make dozens at a time.