Calvin asks Hobbes if he wants to see his transmogrifier. Calvin says he just got it, which is a cardboard box sitting upside down. He explains you just step in, set the dials, then turn into whatever you want. Hobbes is amazed at what they can do with corrugated cardboard these days.

Calvin shows Hobbes that you can set the transmogrifier dial to whatever you want. He explains that the machine restructures your chemical configuration. You can be an eel, a baboon, a giant bug, or a dinosaur. The arrow on the side of the box can point to those choices. Hobbes wonders what happens if you want to be something else. Calvin explains he left some room, so you can just write it on the side.

Calvin asks Hobbes if he wants to be transmogrified. Hobbes thinks being a tiger is his area of expertise. Calvin tells him not to worry, the change is painless and instantaneous. Calvin tells Hobbes to just think, he could be a 500-story tall gastropod, a slug the size of the Chrysler building. Hobbes rolls his eyes and sticks out his tongue. He wonders how he can refuse. Calvin tells him that if he doesn't want to be that, to pick something else. Calvin doesn't care.

Calvin is impatient with Hobbes. He says he'll go into the transmogrifier first. Hobbes wants to know what the point is to changing yourself into something else. Calvin tells him to think of the knowledge gained. Hobbes comments on what horrors we visit upon ourselves in the name of science. From inside the box, Calvin tells Hobbes to set it to "lungfish", then changes his mind to "musk ox", no wait...

Hobbes asks what Calvin is going to transmogrify into. Calvin thinks maybe a tiger. Hobbes thinks that's a great idea, because the world can always use another tiger. Hobbes sets the control and ZAP! Hobbes asks if it worked. Calvin says that he's hot and wonders how Hobbes can stand to have all that fur.

Hobbes asks Calvin if he's a tiger now. He replies yes. Hobbes lifts the box. He looks down on a Calvin-sized version of himself, complete with furry cheeks. Hobbes states that words fail him. Calvin says he's disappointed, too. He reminds Hobbes that transmogrification is a new technology.

Hobbes asks Calvin what it's like to be a tiger. Calvin replies that it's kinda fuzzy, but not much different. They look at each other and Hobbes asks what Calvin wants to talk about. Calvin asks if they eat soon.

Calvin comes into the kitchen and asks Mom if she'll make him and Hobbes a tuna fish sandwich. Mom says she thought Calvin didn't like tuna fish. Calvin tells her that he does now, because he's a tiger. Mom asks if Hobbes is a tiger. Calvin says yes, and he is since he transmogrified. Mom understands. Calvin, the tiger, thinks she's bearing up well under the strain but that she'll crack soon.

Dad comes home, and Calvin asks if he notices anything different about him. Dad guesses a new haircut. Calvin asks if he went blind. Calvin says he's a tiger. Dad says he thought Calvin meant BESIDES him being a tiger. He then tells Calvin he's tired, as Mom yells from the kitchen that she hopes Dad wants tuna for dinner.

Calvin decides he wasn't meant to be a tiger, so he is going to change back. He has Hobbes set the switch to turn him back to "Calvin" and ZAP! As Hobbes says "OOPS!", Calvin comes out from the box looking like a frog. He tells Hobbes to "try again, lunkhead".

Calvin comes out from his box looking himself. Hobbes compliments him on how well his machine works. They're trying to decide what to do with it next. As Susie walks by, Calvin says he could turn her into a bowl of chowder if he could just get her into the machine. Susie will have no part of it, though. She tells Calvin to leave her out of his life's plans.