The Shaggy D.A. (1976)

Director: Robert Stevenson
Cast: Dean Jones, Dick Van Patten, Jo Anne Worley, Keenan Wynn, Shane Sinutko, Suzanne Pleshette, Tim Conway, Vic Tayback

Synopsis:

Wilby Daniels, a successful lawyer running for District Attorney, suddenly finds himself being transformed into an English sheepdog. Somehow he has to keep his change a secret and find just what is causing it, all the while eluding the local dog catcher.