The Moha is a large, amorphous creature whose form is composed of an organic sludge, the colour of which varies by geographical region. The creature's body is not differentiated into tissues or even cells, though nuclei are visible under a strong lens. Biologically it appears to be related to mundane slime moulds, but amplified in size and capability.
The creature starts out life as as small, formless blob, near indistinguishable from its natural cousins. Over the course of the next few months it feeds and multiplies until it can no longer sustain its shapeless form. At this point it will gather and absorb objects from its surroundings and use them to build a "skeleton" that it uses as a frame to grow around. The skeleton is always built in the shape of a generic quadrupedal animal, alhough the creature does not mimic any specific species and always retains a fluid, amorphous appearance throughout. It bears feature such as 'mouth' and 'eyesockets' but these are cosmetic and do not appear to have any function. The skeleton itself is constructed of whatever objects the moha can find in its environment - in the wilds it will use stones and branches, while in civilised areas it will build from manmade items. As it grows it may discard smaller or broken objects and replace them as required.
The moha is a detritivore, feeding on dead wood or other organic material, including human rubbish if it is available. It moves slowly, by extending pseudopods from its 'feet', and only lifts its legs when it needs to increase its speed from a crawl to a walk. It appears to rely on toxins produced in its sludge to defend itself from predators, but also posesses incredible regenerator capabilities and self-organisation. If its body is torn apart and scattered, the individual globs of sludge left behind can locate one another and reunite, rebuilding their skeleton if needed. It has few natural enemies and a docile, curious disposition about any objects it finds. If it turns out to be food, it will sit over it and absorb it into its body, sometimes remaining still for days while it disgests its meal. It has little interest in humans or other animals and will leave them alone even if they are lying still - only dead matter, preferably in a good state of decay, draws it near. Because of this disinterest is is extremely rare to become bonded to this creature and only a handful of cases are known. Indeed, in some places the moha provides a useful service, breaking down human rubbish heaps.
The exception to this disinterest is other moha. Upon meeting another of its kind, the two moha will stop and investigate one another as they do inanimate objects, letting parts of their body (usually the 'feet') intermingle. They may remain in this state for days before parting, and will swap small portions of sludge which appear as discoloured patches for a few days before being absorbed into the body. Soon after, it will bud off small parts of its body, which grow into new moha.