The title is an obvious play on the nursery rhyme Hot Cross Buns as well as a punny allusion to the basic plot premise.
Bugs is "Experimental Rabbit #46" in the Eureka Hospital Experimental Laboratory, a Paul Revere Foundation (which sports the unlikely slogan 'Hardly a man is now alive'). Bugs lives a pampered life, oblivious to the fact that a scientist plans on switching his brain (or at least his personality, since no surgery is involved) with that of a chicken (said chicken bears no resemblance to McKimson-only character Foghorn Leghorn).
The scientist brings Bugs out to the operating theater, in front of an audience of fellow doctors. Bugs, of course, thinks he's been brought out to perform. He pulls out all the stops, singing, dancing, scatting (ala Danny Kaye) comedy routines (including his impression of Lionel Barrymore), and magic acts. Upon finishing each act, he looks around to see the unimpressed, stern-faced doctors in exactly the same frame position each time ("What a tough audience! It ain't like Saint Joe!"). The scientist attempts to retrieve Bugs but is pushed away. He strikes Bugs with a hammer while the rabbit is in the middle of a scat routine, but Bugs quickly revives and, having failed as the entertainment, becomes a vendor instead, selling hot dogs to the scientists, only to be hammered again. Learning the scientist's intentions, Bugs runs and a chase ensues. Bugs hides in a closet, unaware there was a skeleton in there, and comes out scared. Then he makes a chocolate malt and tries to fool the scientist to think that it is an explosive cocktail which he will use on him by warning him "One more step and I'll blow ya up!", until Bugs reveals the formula consisting of "manganese, phosphorus nitrate, lactic acid and dextrose".
Then, he hides near an oxygen tent disguised as a Boy Scout. Finally, Bugs is rendered helpless with laughing gas and placed on the table. With the metallic mind-switching caps on him and the rather uninterested-looking chicken, the experiment was ready to begin. But at the last minute, he somehow cut the wire connecting to his electrode hat and the scientist ends up clucking like a chicken, while the chicken (with the scientist's mind) states in plain English his hope that the experiment can be reversed ("In our next experiment, we will reverse the procedure, I hope."). Bugs tells the audience, "Looks like Doc is a victim of fowl play!"., And then, he laughs as the cartoon ends.
Before the cartoon starts, the Warner Bros. Entertainment logo is shown in both the Stars of Space Jam: Bugs Bunny video tape and modern airings on CN and Boomerang.
Working Title: The Rabid Rabbit
This was the first Bugs Bunny cartoon in the WB-owned TV packages (released August 1, 1948 or later) to be released.
The cartoon was reissued on November 1959, in the 1959-60 season, around the same time that Unnatural History was released, with the original closing replaced. It is the oldest released post-1948 cartoon to be reissued. Most cartoons from 1948 were reissued in the 1957-59 season.