He’s sort of like Cthulhu: the only one of his kind, who came into the world fully formed to represent the idea of Grinch and nothing else. He’s not the third child of Mr. and Mrs. Grinch, who works as a quantity surveyor, has a love of crosswords and Italian opera, once wanted to be a baseball player and happens to be miserly about Christmas.

Cuthulu is offspring of Nub, who is offspring of Yog Sothoth and has other relatives.

There must be an all knowing Grinch parent and grandparent that is absent and uncaring in his life.