Nasty Jack is a minor character that was featured in the television series, The New Adventures of Winnie the Pooh.
Nasty Jack is the leader of a group of horse thieves, i.e. horses that steal things. According to one song line from the episode, Jack is a thoroughbred, and cannot be outrun. He considers himself to be the "nastiest horse thief." He and his gang come to the town of Rickety Gulch to terrorize the town.
Nasty Jack's only known appearance is in the episode "Paw and Order". The episode's framing device is that the main plot is a play being performed by Winnie the Pooh and friends, which is titled "The Legend of Sheriff Piglet." Jack features as the main villain in the play.
After realizing that Piglet is now the sheriff of the town (as Piglet now possesses the Sheriff badge), Jack makes plans to "trounce" Piglet. The group is able to escape into the Sheriff's office. Jack later intimidates Rabbit into serving his gang banana splits. Tigger attempts a rescue, but Jack just laughs as Tigger gets tangled up in his own lasso. Jack prepares to trounce Piglet, but is confronted by the Masked Bear (Pooh's alter ego). The two engage in a duel using ice cream scoops as weapons. Jack corners the Masked Bear, but a coincidence results in the head horse thief being sent flying into a water trough.
Later, Jack sets a trap for the Masked Bear and captures him and Eeyore. He then challenges Piglet to a showdown. Piglet is able to gather the courage to face Jack, but in a twist of fate, his badge falls off. As Piglet is no longer Sheriff, Jack can no longer trounce him. At Piglet's suggestion, Jack decides to become good, and becomes Sheriff himself, stating that he always wanted to be Sheriff. The rest of the horse gang flees town after their once-villainous leader promises to clean up the town. Jack's final appearance is at the ceremony where Piglet is honored as a hero,and hasn't made another appearance since.
- It is possible that the reason Nasty Jack hates sheriffs and became a horse thief in the first place was because he never had the chance of becoming sheriff himself or nobody ever made him sheriff at all until his run-in with Piglet since he stated that he "always wanted to be sheriff", thus, changing his ways.