For some reason, I felt compelled last night to write this down so here's my idea for a monster. I'll actually start working on a sheet now. 

[hider=Lesser Amorphous Maw]
[b]Physiology:[/b]
The lesser amorphous maw is a type of black slime-like monster commonly thought to be the disembodied mouths of an aberrant being. All types of amorphous maws largely lack anything resembling the basic building block of life, with only certain organs possessing tissues and cells, which in the case of lesser amorphous maws is only their singular lamprey like maw, while the rest of them is composed entirely of an entirely homogeneous black substance. 

Amorphous maws are often mistaken for a species of slime as like many types of slime they are freely able to contort and distort their shape. The similarities end there, however, with amorphous maws being entirely solid unlike slimes and possessing distinct organs which they can manifest or dismiss from their bodies (just the maw in the case of the lesser variety). It is unclear where an amorphous maws organs go when they are not upon its body.

An amorphous maw is driven almost in entirety by its single-minded hunger. This hunger may in part be explained by the fact that an amorphous maw withers away very quickly should it not receive sufficient food, however, this does not explain how or why a maw will continuously eat as long as food is available, nor where all of that mass ends up. Any organic matter passed through a lesser amorphous maw’s mouth will quickly disappear if it cannot escape while inorganic matter will simply be ejected.

Lesser amorphous maws lack almost all senses save for three. Firstly, they can tell where every part of their body is in relation to every other part. Secondly, they can detect the intensity of light on any part of their flesh, though no further visual information can be derived from this. Finally, they possess a superb sense of touch, particularly when it comes to picking up vibrations, this sense is potent enough for an amorphous maw to hear through it. In addition, amorphous maws possess an uncanny ability to translate what sensory information they can get into usable information, allowing them to effectively map their surroundings from sounds and tremors and derive limited information on the materials around them. New and chaotic sources of vibrations, such as those produced by fires, or attacks that fail to produce vibrations, often confuse lesser amorphous maws and without other sense to tell them what’s going on amorphous maws have been known to simply sit in place while they are being killed. 

In terms of physical power a lesser amorphous maw could probably match and even slightly exceed that of a normal human adult, however, their strength is severely hindered by the relatively little force that is required to tear an amorphous maw apart, a feat that could be achieved by most moderately fit humans relatively easily. Furthermore, while crushing and stabbing attacks are relatively pointless against a lesser amorphous maw, physically separating parts from the maw will result in the smaller part dying and losing too much mass overall will kill the maw. 

[b]Neurology:[/b]
Lesser amorphous maws are often mistaken for unintelligent thanks to their resemblance to slimes and often odd behaviours. In actuality, lesser amorphous maws are quite intelligent, comparable to creatures like dogs and their odd behaviours instead owe to their strange means of controlling their bodies, their lack of drive to do anything but eat and their general lack of senses. Rather than control their bodies directly like most other creatures an amorphous maw will effectively program actions into their bodies. On the one hand, this means that amorphous maws are great at performing precise and repetitive tasks, while on the other it means that they are largely unable to react to sudden unfamiliar situations with complex responses. Certain actions the body of an amorphous maw will perform naturally and cannot be overridden, such as ejecting inorganic matter and biting down on anything fleshy that enters its mouth. 

Thanks to their unconventional brains, most forms of mind-reading struggle to pick up upon the deeper thought process of the amorphous maw, but instead the programming that the body is acting upon and the bodies constant analysis of the sensory information it is picking up on, both of which tend to be incomprehensible gibberish to those who don’t know how to interpret them.

[b]Other facts:[/b]
[list][*]A lesser amorphous maw at its largest only weighs around 10 kg. 
[*]While many types of amorphous maws look pretty much identical, lesser ones tend to be smaller and will at most only generate one mouth and no other organs like eyes. 
[*]Though they are known to attack other creatures for food, their lack of strength means that they for the most part scavenge. 
[*]For the part, amorphous maws live in dark places as they avoid light unless they are starving, though light doesn’t actually seem to hurt or hinder them in any way. Lesser amorphous maws.[/list][/hider]