Werewolf

A werewolf (from Old English werewulf: wer, "man", and wulf), also known as a lycanthrope (from the Greek λυκάνθρωπος: λύκος, lykos, "wolf", and ἄνθρωπος, anthrōpos, "man") is cryptid with the ability, whether willing or not, to shapeshift into a wolf or wolf-like human. The affliction is almost universally treated as a curse (be it from bite/scratch from another werewolf, curse from a witch, etc) with the exception of modern werewolves, which have a very high tendency to be romanticized.

Related Links

 * http://monsters.wikia.com/wiki/Werewolf (mostly uncited massive history/mechanics dump)