The article's author, Patrick Houlihan, considers the Set animal 'monsterous' because he thinks it is a composite of one or more animals. Scholars vary on just what it was, a composite, or an animal now extinct:

"The Seth-animal has been connected with the ass, oryx antelope, greyhound, fennec, jerboa, camel, okapi, long-snouted mouse, aardvark or orycteropus, giraffe and a kind of hog or boar. A. S. Jensen 2) drew attention to the fact that it has also been regarded as a hare, jackal, tapir, long-snouted mormyr of the Nile or the nh bird of the Egyptians." TeVelde, _Seth, God of Confusion_, page 13

I've also read suggestions that the now extinct "Sivatherium (the name of which comes from the Hindu god Siva or Shiva, who shares some characteristics with Seth), which is a possible ancestor of the giraffe and okapi, and had strange "horns" or "antlers"" is a possible candidate:

(Originally found at Copyrightexpired.com/)

There's certainly some similarities, but it lacks the sleek body of a greyhound, which we usually see in the Set animal. Predynastic images are often very hard for us to identify as representing Set. Possibly, it took a while for the ancients to come up with the standard Set look that we know and love.

I alternate in opinion between a greyhound type animal made to go extinct and a composite animal rather like the Griffin. The ancients might have come to the conclusion Set's personality is way too vast for just one animal to symbolize him.

What _IS_ certain is that the image of Set seated with legs drawn up follows the form of one of the hieroglyphs for Set:

Source: TeVelde, _Seth, God of Confusion_

While sorting through my files, I found a colored version of this image:

I'd saved this without info, but tracked down a version at the BBC,
and they give credit to Peter Clayton, an author who has written 21 books.
But I still don't know where the actual item exists!

However, I found another very similar Set glyph in an article of KMT magazine: