Jerry Lewis’s Persona, and in some ways a more honest film (1963). Lewis is Dr. Julius Kelp, an absentminded chemist who invents a potion that turns him into the irresistible Buddy Love, a character bearing a not wholly coincidental resemblance to Dean Martin. Even if you don’t find Lewis funny (strangely enough, I sometimes do), The Nutty Professor has to stand as one of the most intense investigations of self ever put on film, a technically impeccable work of inspired megalomania.