The curse of the wolf has taken you, and you now share your body with a wolf spirit. Once a day you take on the form of a werewolf. You gain +10 HP in this form and can only make claw (2d8+4) and bite (2d6) attacks. You last in this form for 1 hour, roll a STR saving throw (DC 18)  to overcome the wolf spirit or if you fall below 9 natural HP.
The wolf spirit has  voice in your mind and a will of his own.