Sauron was not of mortal flesh, he could never again appear fair to the eyes of Men, yet his spirit arose & returned to Mordor. There he dwelt, dark & silent, until he wrought a new guise, an image of malice & hatred made visible; the Eye of Sauron.
One moment only it stared out as from some great window immeasurably high there stabbed a flame of red, the flicker of a piercing Eye. The Eye was not turned on them, it gazed north but Frodo at that dreadful glimpse fell as one stricken mortally.