Plot

Spit and polish Colonel Tucker visits the camp at the worst time during April Fool's Day. Klinger, egged on by Sergeant Rizzo, uses reverse psychology to try to get out of the Army.

No-nonsense Colonel Daniel Webster Tucker (Pat Hingle), a notorious disciplinarian from the Surgeon General's office with a short fuse, visits during an outbreak of April Fool's Day pranks. Daniel can quote Army's medical journals by memory and specializes in Court Martials. The gang at MASH 4077 is celebrating a whole of April fool pranks and they don't spare even Mulcahy. Compressed foam in Winchester's praline canister, dead minnows in Houlihan's pockets. Fox tail attached to Potter's uniform. They even steal Mulcahy's robe from the shower and leave him a female evening house frock. Oatmeal in Hawkeye's boots. Potter makes Klinger order everything in inventory and even more order forms.

Potter tries to put a stop to the mayhem (he issues a unit wide alert to be on their best behavior), which includes Klinger taking Rizzo's advice to use reverse psychology as his latest ploy to gain a discharge (You can do anything in the army, just act like you don't want to do it). The army always does the opposite. So, if you want out, act like you want to stay in forever. Rizzo doesn't understand this, as for him the army is place where he can be a bum and get paid for it. But Margaret has pulled one too many pranks on Hakweye and he is hankering for revenge. He removes the canvas from Margaret's tent without touching any of its belongings. Margaret is shaking down Hawkeye for the location of her tent, when Daniel drives in. Daniel is livid to see officers having a pillow fight in the compound. Klinger saves the day by arriving in proper military gear and shows Daniel to his tent. Potter is furious at his officers for countermanding his direct orders. He knows that the inspection will go badly now.

The next day Winchester and BJ perform difficult surgical procedures and Potter applauds them. Daniel doesn't think the doctors deserve any praise for simply doing their work. He also gives them hell in post op and tries to interfere in the treatment of patients. The doctors protest Daniel's attitude. BJ, Hawkeye, Winchester and Margaret take him outside and try to reason with him. Daniel puts them all on report for gross insubordination and initiates court martial proceedings against them. He wants to bar them from medical service.

Daniel seeks Klinger and and finds Queen Cleopatra instead. Klinger says he is filling out the daily reports and next he will get the Cols jeep lubed and serviced. Daniel thinks that the MASH 4077 has got to Klinger and turned the only decent soldier in the place loco.. He is ready to grant Klinger a section 8 and promises to take him when he leaves. The gang decides to play a joke on Daniel (to deserve their punishment that they think they are already getting) and pour a full bucket of beer on him as he walks into the mess tent. Daniel has a heart attack. Turns out Daniel was faking the whole thing and was in cahoots with Potter, who planned this whole thing weeks ago. The icing on the cake is that Klinger thinks he is getting the section 8..