Professor Alastor 'Mad-Eye' Moody
Alastor "Mad-Eye" Moody is a former Auror. His profession has apparently been rather hard on him, as he has a wooden leg, a magical artificial eye, and a large chunk taken out of his nose. He has developed a deep distrust of nearly everyone and everything. His nickname is derived from his magical eye, which is forever swiveling, totally independently of his real eye.