Werewolves

Werewolves were a wolf-like race that lived on Wizard's Isle and the woods of Beleriand. Possessed by evil souls, they haunted Middle-earth and preyed upon Elves and Men who had the misfortune of crossing their path.

History
Werewolves were descended from Draugluin and were made by Sauron, who sent evil spirits to inhabit the bodies of wolf-like beasts. More ferocious than any other kind of wolf, they lived on Wizard's Isle from where they spread into the forests, making them a dangerous place for woodsmen and travellers.

After Beren, Finrod and their company were imprisoned by Sauron, the latter sent Werewolves to the dungeons to eat the captives one by one, so as to intimidate them and make them reveal their intents. Not long after, Lúthien and Huan came to Wizard's Isle and the Werewolves were tasked with capturing her. Huan, however, was able to best them all, even Sauron in wolf-shape. The greatest of their race was Carcharoth - bred by Morgoth - who guarded the gate of Angband.