The first transmogrifier Calvin invents consists of an upside-down cardboard box with the word "transmogrifier" written on the side in pen. A dial on the side of the box may be pointed towards one of several settings, also marked on the box in pen. More settings can be added by simply marking them around the dial. A button initiates the transmogrification process, turning the thing under the box into whatever is indicated on the dial. Calvin used his transmogrifier to great effect in the comic strip, transforming himself into a tiger, dinosaur, 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. The hedonistic pleasures of this device have no end, as things can be replicated infinitely and the best part is that the objects that have been trasmogrified can only be seen by the transmogrifee.