The tail of the timberwolf

The Cutie Mark Crusaders are excited about celebrating Zipporwhill's birthday, then, during the party, a timberwolf appears, and when it seems to be more interested in candy than the ponies, their new friend, Lilymoon, suspects they are dealing with a werepony, half pony and half timberworlf, and the Cutie Mark Crusaders are on the case.