[The Barrow-Wight]

There weren't a lot of color changing eyes, but there certainly were a lot of flashing ones. Especially if your names started with 'G'.

Gandalf’s eyes flashed. 'It will be my turn to get angry soon,’ he said. 'If you say that again, I shall. Then you will see Gandalf the Grey uncloaked.’

‘No!’ cried Gandalf, springing to his feet. ‘With that power I should have power too great and terrible. And over me the Ring would gain a power still greater and more deadly.’ His eyes flashed and his face was lit as by a fire within. ‘Do not tempt me! ....

‘Don’t be a fool! What have you heard, and why did you listen?’ Gandalf’s eyes flashed and his brows stuck out like bristles.

'You were less tender to me,' said Glóin with a flash of his eyes as old memories were stirred of his imprisonment in the deep places of the Elven-king's halls.

Gimli rose and planted his feet firmly apart: his hand gripped the handle of his axe, and his dark eyes flashed. 'Give me your name, horse-master, and I will give you mine, and more besides,' he said.