When Professor Potter attempts to demonstrate his new telepathic helmet at the Metropolis Zoo at the same moment that Jimmy Olsen activates his signal watch, the mind of Jimmy is switched with that of a nearby gorilla. Unable to effect a reversal, Superman creates a sanctuary for the gorilla-controlled body of Olsen, while the cub-reporter-controlled body of the gorilla resumes Jimmy's journalistic career. Clad in an ill-fitting suit and dubbed "Bonzo" by Perry White, the gorilla reporter covers several ape-themed stories for the Daily Planet, including a wrestling match between Golden George and the hirsute Gorilla, and the premiere of a science fiction film about a simian policeman featuring Zimba, a trained gorilla. Later, "Bonzo" Olsen goes on patrol with Superman and performs several super-feats before the Man of Steel is "struck by a strange idea" and realizes that it was Jimmy's "ultrasonic signal that altered the telepathizer machine and caused the mind-exchange," paving the way for a reversal and a return to normalcy for Olsen (SPJO No. 24/2, Oct 1957: "The Gorilla Reporter").