The sound came hissing louder and sharper, and as he looked towards it, to his alarm Bilbo now saw two small points of light peering at him. As suspicion grew in Gollum’s mind, the light of his eyes burned with a pale flame. “What have you lost?” Bilbo persisted. But now the light in Gollum’s eyes had become a green fire, and it was coming swiftly nearer.
"I saw that the eyes that glanced at me shone with a pale-green light. I did not know then that a reddish luminosity, at least, is not uncommon in human eyes. The thing came to me as stark inhumanity. That black figure with its eyes of fire struck down through all my adult thoughts and feelings, and for a moment the forgotten horrors of childhood came back to my mind."
- HG Wells, "The Island of Doctor Moreau"
