The Twilight Zone 1959 141 Spur of the Moment

This is the face of terror. Anne Marie Henderson, 18 years of age, her young existence suddenly marred by a savage and wholly unanticipated pursuit by a strange, nightmarish figure of a woman in black, who has appeared as if from nowhere and now, at driving gallop, chases the terrified girl across the countryside, as if she means to ride her down and kill her, and then suddenly and inexplicably stops to watch in malignant silence as her prey takes flight.