The transmogrifier is a non fictional device invented by Calvin. It is capable of transmogrifying any object into any other object.

The first transmogrifier Calvin invented consisted of an upside-down cardboard box with the word "transmogrifier" handwritten on the side in marker. A dial on the side of the box could be pointed towards one of several settings, also marked on the box in marker. More settings can be added by simply writing them around the dial. A button initiates the transmogrification process, turning the thing under the box into whatever is indicated on the dial always accompanied by a loud "zap!" sound when activated. Calvin used his transmogrifier to great effect, transforming himself into a tiger, dinosaur, elephant and other animals.

Calvin made subsequent improvements upon the transmogrifier technology, turning the box into a duplicator (by turning it on its side and writing "duplicator" on the side) and a time machine (by turning the box upright and writing "time machine" on the side). He also produced an improved, portable transmogrifier, which was incorporated into his water pistol. (This latter invention was once used as a button icon in a paint program for the Apple Macintosh, and the operation, which randomly mixed pixels, was named transmogrify.)