Disappearing Samantha (S02E29)

Darrin is assigned to publicize Osgood Rightmire, who makes a career of debunking witchcraft. The Stephens attend a lecture given by Osgood with Louise and Larry Tate. When Rightmire dramatically offers himself as a target for any witch, Samantha twitches her nose. Rightmire trips, setting off a series of mishaps. Rightmire pronounces an incantation which he asserts would cause any witch to disappear, if there were such things. (iTunes)