Lycanthrope n pl. lycanthropes/ a person with the form and appetite of a wolf. A werewolf.

Lycanthropy n / the condition of being under a compulsion or curse that causes periodic transformations into a beast.

Werewolf n pl. werewolves/ (in stories) a man or woman who sometimes becomes an animal (i.e. a wolf).

Transformation n / (an example of) the act of changing completely in form, appearance or nature.