The Eye Of Sauron

The Necromancer. 

The symbol of the chief lieutenant of the Dark Lord, Morgoth. At one time taking on the form of a werewolf and a vampire bat. AKA, The Red Eye, the Lidless Eye, or the Evil Eye. 

“The Eye was rimmed with fire, but was itself glazed, yellow as a cat’s, watchful and intent, and the black slit of its pupil opened on a pit, a window into nothing.”