Two areas will be considered in today's update. First of all, the mouth. The Otyugh is described as having a sucker-like mouth that's full of teeth, and one or two of my previous scribbles have suggested how this might look. The scribble below goes into a bit more detail:
If we run with the idea that Otyugh is a sort of dungeon hoover, this area would usually be busy chowing down on various nasty things. At the same time, this also suggests that the whole mouth and throat is like a nozzle and a pipe - only a lot more dangerous. It also occurred to me that the mouth and teeth might be able to extend a little in order for the monster to get more of a bite, and this is what I've suggested in the lower part of the scribble above. The overall look is a cross between a pig's snout and a shark or lamprey mouth. If we zoom in on the only solid part of the whole area, a tooth looks like this:
The idea here is that the teeth are scooped shard-like pieces arrayed inside the mouth. These would act both to cut and perhaps also to rotate backwards from the root to convey it's food into the mouth. Imagine hundreds of these teeth acting in unison and the Otyugh seems more like a garbage disposal unit - which is effectively what it is.
The second point for consideration is how the monster might appear under the surface. I don't imagine the Otyugh having a skeletal structure in any practical sense:
Instead there's a main spine-like cartilaginous mass running along the top of the body, which is flexible but tough and acts as an anchor point for both the internal organs and the outer muscle layers. You can see more of this in the cross-section detail below:
|Seen from the front: (A) skin/hide (B) muscle layer (C) internal organs|
The upper left of the scribble is a section of the 'spine' as seen from the side; the detail in the bottom left shows the underside of a spine section with the tendon, etc attachments to the internal organs. The greater mass of the Otyugh is still fleshy lumps of muscle and organs. The spine, teeth, eyes and tentacle edges are made of tougher, solid stuff but the overall design is still one which is both flexible and resilient.
Next up for consideration is how the muscle mass might work and be arranged around what I've shown in the above scribbles...