he's a mean one
Grinches are monstrous humanoids that generally live lives of miserable self-imposed exile. They make their homes in remote lairs high atop mountain peaks that are impassible to most other creatures, sometimes reaching heights of 10,000 feet up. Grinches are extermely rare, so much so that in any given location the resident grinch is thought of as the only one of its kind and is thus referred to simply as 'the grinch'.
Appearance
The 'typical' grinch stands roughly five and half feet tall and is covered in mangy green fur, though older specimens may appear almost black and white. On their heads grinch fur shoots up in a single clump which dangles back down over their faces. They wear little clothing aside from crude collars and shoes that they make out of the slimy vegetation that lines the walls of their junk strewn cavern homes.Their bones are composed entirely of cartilage which, in addition to causing extreme facial distortions with each mood change, allows grinches to undulate their spines if they so choose, allowing them to slither and slink with smiles most unpleasant.
Their diets consist mostly of spoiled meats and rotten vegetation, the breakdown of which causes massive gaseous buildups that bloat and distort the grinch abdomen to extreme proportions. This foul smelling gas is released frequently through pores all over the grinch's skin. Combined with the grinch's complete lack of hygene, this creates a unique and easily identifiable odor that arrives before the grinch does, and lingers long after his passing through. Indeed the three words that best describe them are as follow, and I quote: "Stink,stank,stunk"
Combat
It should be noted that while grinches appear to be flabby creatures with weak arms and spindly legs, they are about as strong as the average human. They also have the ability, in times of extreme need, to multiply their strength by a factor of twelve so that they have the strength of ten grinches, plus two. This strength, while impressive in short bursts, cannot be maintained for long by the grinch without the risk of severe pulmonary failure due to their aortas being two sizes too small.
Ecology
Out of necessity, grinches are excellent craftsmen, creating everything they need in short fashion out of whatever meager elements are available to them. The crudeness of material tends to give the fashioned items a primitive , rickety look, but this is deceiving. Grinch sleighs are capable of carrying huge cargoes that would crush conventional counterparts.
While grinches insist that they prefer their solitary lifestyle, they do have an undeniable need to be near others. Grinch lairs, as stated, are always in the vicinity of who settlements. In addition, grinches are known to keep animal companions. While they treat these poor animals with the same miserable attitude they do everyone else, they never directly mistreat them. Also, should grinch ever be welcomed in by another being, the will eventually drop their hermit tendencies and embrace their new friends.
It is thought that grinches, rather than being a true race, may be some form of mutated who- a small, peaceful humanoid race. This is supported by the fact that grinches are always located near who communities and that no female grinch has ever been observed. Unfortunately for the whos, the natural distempered nature of the grinches ensures that the one that has roosted near their community is a mean one.
(Note: this same desire to be close, but not too close, to others can also be found in the Grinch's urban cousin, the trash-dwelling Grouch)
Lastly, recent reports have suggested that grinches and whos are sub-dimensional creatures so small that their entire world exists in the crystals of a snowflake. This is, of course, a complete load, created by people who want to ruin a perfectly written story.