Of course it isn't human, but neither are a thousand other beings described and depicted on this forum. You don't think the same things about cartoon characters with their distended heads? Or the RTD healing golems? Or DF's titans and forgotten beasts? So many things that are so flawed, so distorted, or so Other. Those here make things like that, and worse, regularly in their games; for entertainment. To generate similar images in their imagination, with far greater detail and solidity.
What makes this one special?
It's obviously undead, although it could be of ghost or zombie (because of the chest shading). It lost an arm at some point, and replaced its left hand with a broken right hand. The nose was broken, and the mouth was definitely cut the way it is now, although the symmetry makes me think it was from a controlled method of injury other than torture. The expanded appearance (in addition to a large figure), and the hair make me think drowning was the cause of death. Although another, more immediate, possibility is that it eats things to absorb them, like that old Jeepers Creepers thing. Although it's probably not proactive in this endeavor, considering it's still ill equipped.
It obviously has history... and is that was makes it so disturbing? ;⌡ A creature from Beyond that didn't just appear from nothingness a short time ago?