Calvin shows Hobbes the latest perfection in technology. Hobbes looks at it and asks "A water pistol". Calvin tells him it's the new, improved version of the transmogrifier. Now you just point at whatever you want to transmogrify. Calvin gives an example of not liking the color of your bedspread and presto, it's an iguana. Hobbes can imagine the myriad of uses of a hand-held iguana maker.

Hobbes asks how the gun knows what to transmogrify things into. Calvin replies "telepathy". The gun reads brain waves and turns the object into whatever you want. Calvin says it took him all morning to invent. Hobbes points the gun at Calvin. He says he's thinking about a big slab or grilled tuna. Calvin yells for him to watch where he's pointing the gun.

Calvin wants to test the transmogrifier gun. He wants Hobbes to think of a pterodactyl. Calvin says he'll terrorize the neighborhood for awhile. Then, Hobbes can change him back into a boy when the National Guard comes. Hobbes doesn't know what a pterodactyl is. Hobbes asks if it's a bug. Calvin tells him it's a big flying dinosaur, but tells him not to shoot if he doesn't know what it is.

Hobbes changes Calvin into a chicken. Calvin yells at Hobbes. He was supposed to change him into a pterodactyl. Calvin, the chicken, asks why he thought of a chicken instead of a pterodactyl. Hobbes says it was because it was almost lunchtime. Calvin continues to badger Hobbes by saying that he's glad Hobbes wasn't hungry for a hot dog.

Calvin, the chicken, gives the gun back to Hobbes and tells him to try again. He says he wants to be a pterodactyl. ZAP! Calvin proudly looks at himself. He says that's more like it. We see Calvin as a minuscule pterodactyl next to Hobbes. Calvin asks when Hobbes turned himself into a 200-foot-tall colossus. Hobbes says he didn't, why?

Now Calvin complains that he's a tiny pterodactyl. Hobbes says big dinosaurs give him the willies. Calvin asks how he's going to terrorize the neighborhood like that. Hobbes accuses him of being cranky today. Calvin grabs the gun and says he'll show Hobbes. ZAP! Hobbes, the duck, says Calvin just made a big mistake.

They bicker with each other. Hobbes grabs the transmogrifier gun and says he'll fix Calvin up right. ZAP! He turns Calvin into a big pig. Outraged, Calvin turns Hobbes into a monkey. Insulted, Hobbes zaps Calvin into a flower. Hobbes gets zapped into being an alligator. ZAP! Calvin is now an aardvark. Much later, they rest. Calvin is an owl, and Hobbes is a purple monster. The owl can't remember who is who. The purple monster tells him he hopes Calvin is the owl, because his Mom is going to have a fit when she sees this.

They agree to change each other back to their original selves. Calvin, the owl, zaps the purple monster back into Hobbes. Hobbes points the gun at Calvin and....click...click...click. Calvin says he's not changing. Hobbes is glad they did him first.

Calvin wonders why it won't work. Hobbes says that since Calvin invented it, he should tell Hobbes. Calvin worries about being stuck as an owl. Hobbes figures they can catch mice in the back yard for Calvin to eat. Calvin wonders what he'll do. Hobbes goes on to say he couldn't eat a mouse raw. He thinks their little feet are real cold going down. Calvin yells for Hobbes to forget about the mice and help him think. Hobbes scratches his head and wonders if a pet store will sell you a mouse if they know you're going to eat it.

Calvin trudges into the house and tells Mom that he's an owl. Mom says he doesn't look like a very happy owl. Mom suggests maybe some lunch would help. Calvin doubts it, he doesn't like mice. Mom gives him some soup. He asks if it's mouse soup. He doesn't like mice. Mom tells him she heard him, and that the soup is tomato.

Calvin is complaining that he can't be an owl forever. He asks Hobbes how he'll change back with the transmogrifier gun broken. Hobbes suggests he should just accept the predicament. He says it's probably better Calvin is an owl instead of a kid. Calvin shouts and wonders how it could be better. Hobbes tells him he didn't know how to bring it up before, but little boys don't smell so good.

Calvin is worried about going to school as an owl. He covers his head with his wings and says he's doomed. Hobbes asks since when do owls go to school. Calvin thinks and breaks out into a chorus of "Zip-a-dee-doo-dah, zip-a-dee-ay, my oh my, what a wonderful day".

Mom tells Calvin to get up from bed. He's going to be late for school. Calvin says he's not going to school, since he's an owl. Mom disagrees and tells Calvin to get dressed. Calvin sees he's not an owl. He says the transmogrification must be temporary. He's back to being a kid. Hooray! Except that means, he can go to school. Hobbes tells him to keep the shade down when he goes.