Bonkers from Yonkers
In Mario Brothers Plumbing, Mario and Luigi are in the process of putting together a large piping system while a large amount of steam swirls around them. Unfortunately, Luigi accidentally hits Mario on the head with a pipe, dazing him. Noticing how Mario is staggering from being hit, Luigi begins to guide him to a nearby couch as he emits bizarre noises.
Leaving Mario to sit on the couch, Luigi rushes to a nearby phone book and begins to look through it; finding the number he is looking for, Luigi, grabbing a nearby phone, begins to dial the number while telling Mario to remain calm. Getting an answer on the other end of the phone, Luigi asks if he is speaking to Dr. Sigmund Fruitcake, a famous "head doctor". The person at the other end of the phone says that they are Dr. Fruitcake and, after hearing Luigi's story about Mario's head injury, decides to come right over to Mario Brothers Plumbing.
Hearing the Dr. Fruitcake will be coming over, Luigi hangs-up the phone, when suddenly, the doorbell of Mario Brothers Plumbing rings. Dr. Fruitcake suddenly opens the door to the apartment, surprising Luigi. Entering the apartment, Dr. Fruitcake introduces himself and proceeds to tell Luigi how unusual his head is, though he also says that, aside from it's ugliness and hairiness, he sees nothing wrong with it.
Luigi, somewhat insulted, tells Dr. Fruitcake that it isn't him with the head problem, it's his brother, Mario, who, after being hit on the head, believes himself to be a bird. Dr. Fruitcake tells Luigi that everything with Mario should be fine, but retracts this statement when he hears Mario begin to frantically make chicken noises. Intrigued, Dr. Fruitcake takes a closer look at Mario, saying this is quite bizarre.
Much later, Luigi calls a cranky Dr. Fruitcake in the middle of the night, telling Dr. Fruitcake that he has to come back to Mario Brothers Plumbing to give Mario some more therapy. Dr. Fruitcake asks why he has to go back and see Mario, as his therapy cured Mario of his delusion that he was a chicken; Luigi tells Dr. Fruitcake that it did, though Mario doesn't believe he's a chicken anymore, he now believes himself to be a monkey.
Putting Dr. Fruitcake on hold, Luigi begins trying to tell Mario, who is hanging upside-down from a ceiling pipe, to get down on the floor. Grabbing the phone, Luigi tells Dr. Fruitcake that he wants him to make Mario believe he's a chicken again, saying that he could "use the eggs".
Dr. Fruitcake, having traveled to Mario Brothers Plumbing, begins trying to calm down Mario, who is gorging on bananas. After a brief discussion with Luigi over Mario's state of mind and after telling several bad jokes, Dr. Fruitcake decides to use some "thought-transfer therapy" on Mario, claiming that the thoughts will leave Mario and go elsewhere, but who cares where? After yelling "I am not a chicken!" and "I am not a monkey!" at Mario several times, Dr. Fruitcake finally succeeds in restoring Mario to normal. Unfortunately, as Mario points out to Dr. Fruitcake, Luigi has begun to believe he is a chicken.