The Horse's Mouth (S02E25)

A horse named Dalleyrand escapes from the horse trailer of Jack Spindler in front of the Stephens home. Unable to talk to the horse, Samantha turns her into a women named Dolly. Dolly tells Samantha she has forced to set a fast pace and tire the horses out so her sister, Adorable Diane, can win. Samantha invites Dolly to rest up at the Stephens home. Darrin arrives with Gus Walters, who needs money to market a new invention. Dolly suggests they go to the track where she can make money for him by picking winners. Samantha shocks Darrin when she tells him- Gus can't lose because Dolly really is a racehorse. (iTunes)