Calvin and Hobbes cardboard box
A transmogrification in process.
The Transmogrifier is an invention of Calvin's that would turn one thing into another. Like most of his inventions, it was made originally from a cardboard box, though a later model was made using a water gun. Calvin used the transmogrifiers many times, turning himself and Hobbes into quite a wide array of creatures. The transmogrifier first appeared on March 23, 1987.
Appearance and effects
The transmogrifier is an upside-down cardboard box with a dial on the side that could be set to whatever the user wished to be turned into. The problem is that only Calvin and Hobbes can see whatever they turned into, so all the other people still see him as a kid. This was eventually fixed, however, because when Calvin turned his duplicates into worms, his mother saw them as worms as well. Extra space was left on the side of the box so that if the user wanted to turn into something not listed, it could be written in. The test run of the transmogrifier was largely a success, with Calvin being turned into a tiger for a day (or about a week's worth of strips).
The second version of the transmogrifier came in the form of a water pistol. According to Calvin, when fired, it read the mind of the user and transmogrified the object it pointed at to whatever they thought of. Hobbes remarked that it was ingenious, prompting Calvin to reply that "it took me all morning." The transmogrifier gun later saved his life when he floated away on a balloon, which popped high in the air. He came across it in his pocket while looking for gum to blow a bubble, and accidentally turned himself into a safe (he thought "I'm safe!" and the transmogrifier took him literally, turning him into a safe), then a light particle. He made it home just in time for dinner, but upon seeing what was on his plate, he grumbled that had he known, he wouldn't have been in such a hurry.
Calvin as a frog.The transmogrifier's dial is an arrow that is turned to a setting, which is whatever animal, plant, or thing you want. Originally, the dial had only the settings "Eel", "Baboon", "Bug", and "Dinosaur", but Calvin left room to write more names on the box. During its first trial, "Calvin" and "Tiger" settings were added for Calvin to turn into a tiger and back. There also must have been a "Toad" or a "Frog" setting added, because Hobbes accidentally turned Calvin into one while attempting to turn him back to a human. A "Worm" setting was eventually added as well, allowing Calvin to trick his duplicates. There was also an "elephant" setting added, so he wouldn't forget his vocabulary words.