The below description is taken from LEGO.com.
Whenever the full moon rises high in the night sky, the Werewolf undergoes a startling transformation into a half-man, half-beast creature. Unable to control his primal instincts, he rampages across the countryside, terrifying all who encounter him!
...Okay, he actually just digs holes, buries chew toys in the yard, and romps around the park fetching sticks. It's all a little embarrassing for the Werewolf, so if you happen to see him running around in circles trying to catch his own tail, please try to act scared. It'll mean a lot to him.