Not the Worst Thing He Could Mean by “The Whacker”

Sunday school teacher (showing picture of Good Shepherd): Who can tell me who this is?
Kid: That's Jesus with the whacker!
Teacher (puzzled): You mean he takes the sheep out for a walk?
Kid (pointing to the shepherd's crook): No, when one of the sheep tries to get away from Jesus, he whacks them with it so they won't go!