"You canker blossom!" 3 Shakespearean Insults
(1886) A novel by Robert Louis Stevenson about the good Dr. Jekyll, whose well-intentioned experiments on himself periodically turn him into the cruel and sadistic Mr. Hyde.
Note: Dr. Jekyll and Mr. Hyde provide a classic example of split personality. In addition, the two characters often serve as symbols of the good and evil sides of a single personality.