"A Case of Ed" is the 18th episode of Season 4 and the 95th episode of Ed, Edd n Eddy. In this episode, Edd buys an Encyclopedia of Obscure Diseases, and become convinced that he is suffering from a fatal illness when he notices that they symptoms for it describe him perfectly. Not one to waste a pranking opportunity, Eddy uses Edd's sudden hypochondria to entertain himself–that is, when he and Ed aren't busy taunting Kevin, who has been grounded and cannot retaliate.
Kevin stands in a window, staring out grumpily as rolls of toilet paper go flying by and land on his house. The source of these rolls are Ed and Eddy, and the reason that they're even able to do this is explained by Eddy to a disturbed Jimmy: Kevin has been grounded, and so he won't be able to get back at them–at least, not for a while. However, soon the duo's merrymaking is interrupted, as Edd arrives, towing behind him a wagon full of used books that he procured from a library sale.
Wanting to share the joy of knowledge with his friends, he picks up one of the books and begins reading from it at random. This book is an Encyclopedia of Obscure Diseases, and the page he is reading details the symptoms of an affliction known as Lackadaisycathro Disease; symptoms which include the rationalization of mundane circumstances, habitual cleanliness, and an abnormal fixation to headwear. Of course, as soon as Edd finishes this description, he is quite worried, as these symptoms are a dead ringer for his personality.
The other two Eds recognize this as well, but Eddy and Ed choose to dismiss it and instead bother Kevin some more. However, when Edd continues to fret after reading more of the symptoms of the disease, Eddy soon makes a joke about how he looks a little sick. Taking this to heart, Edd collapses, giving Eddy the idea to prank Edd by taking advantage of his worried state.
Soon enough, Edd is dressed in a hospital gown, waiting to be seen by Dr. Ed. When Edd is naturally uncertain that Ed is qualified to perform medical procedures, Eddy proceeds to silence him by pointing out that confusion is yet another symptom. After this, Edd is subjected to several physical tests by Ed, most of which make no sense and seem to have been made up on the spot.
After these tests, Edd fears the worst, as he's obviously expiring. Eddy then asks if anybody has tried to kick him; upon receiving a "no", he says that Edd is in the clear, as people trying to kick the disease-bearer is the final symptom while surreptitiously slapping a "Kick Me" sign on Edd's back. Edd is relieved by this news until Eddy kicks him, sending him skyward. Eddy then fakes shock, saying that he thought Edd didn't have the final symptom. Worried, Edd asks Dr. Ed how long he has to live and Ed, not being the brightest bulb in the box, suggests that Edd has until lunch. Edd nearly faints when he hears this, but is revived somewhat when Eddy slips a piece of paper and a pencil into his hand and tells him to write. Edd asks if he's supposed to write a sonnet on the beauty of life, but as usual, Eddy is thinking only of himself, and tells Edd to write out his will, and leave something nice to him. Ed asks for Edd's hat, and this is the final straw, as he goes off wailing about how he is not long for this world. Eddy bursts into laughter, but Ed starts to cry, having been caught up in the charade; Ed's tears quickly turn to smiles when Eddy reminds him that they're pranking Edd, however.
Edd wanders around the cul-de-sac and sees most of the kids coming down the lane, heading for the beach. They invite Edd to join them but, depressed, he can only cry about how little time he has left. He has taken Eddy's advice, however, and is giving his stuff away. To Rolf he bequeathes his microscope, which Rolf mistakes for a peanut-smasher, and to Jonny he gives his remote control. Edd then turns to Nazz and bemoans the fact that there are so many things left unsaid between them; when Nazz asks what they are, however, he just turns away, weeping. This exposes his back and the Kick Me sign to Jimmy, who swiftly walks up and dispenses a light kick, giggling all the way. Jimmy's merriment soon turns to confusion, however, as Edd wails about the horror of Lackadaisical Cathro Disease–only for Nazz to peel the sticky note from his back and show it to him. As Edd catches on to what his friends did to him, the other kids walk off, ready to head for the beach.
Ed and Eddy are still having fun at Kevin's expense by building a wall around his house, when Edd comes back, steaming with rage and demanding to know why they would do something so evil to him. Eddy tries to brush him off, but is soon distracted by the specter of Kevin on the outside now. Kevin explains that he got off earlier for good behavior, and Eddy first grovels, then runs away with Ed and hides in his house and locks the door. Kevin growls as Ed and Eddy happily dance around inside, having escaped his rage again, but is soon distracted by Edd, who happens to have Eddy's spare house key and is only too glad to "misplace" it somewhere that Kevin can find it. Kevin is all too willing to play along, and Ed and Eddy are soon on the receiving end of a thrashing that Edd deems part of "Kevin's Justified Pummel Disorder".
Edd: [holding up a book] "Nocturnal burrowing insects." Ed: "Cool!" Edd: [picking another book] "The Enchanted Spleen." Ed: "Compelling!" Edd: [showing Ed a third book] "Scores of Spores." Ed: "I can relate!" Edd: [selecting book number 4] "One hundred and one Latin party jokes." Ed: "Do tell." Edd: [picking up a heavy looking book] "The Encyclopedia of Obscure Diseases. This looks edifying. Listen to this, Ed. The Lackadaisycathro Disease. Symptoms include the rationalizing of mundane circumstances, habitual cleanliness and an abnormal fixation to headwear…" [he trails off] Ed: "That sounds resembling! 'Cause it sounds like… uh…" Eddy: "It sounds like Sockhead, bonehead!"
Rolf: [talking about the microscope Edd gave him] "A peanut smasher?" Edd: [lamenting] "OH, ROLF! YOU'RE SO UNEDUCATED!"
Eddy: "Nice shorts, Romeo." [Edd tries to cover his noticeable underwear showing with his hospital gown.] Ed: [to the trembling Edd] "Please, rest your buttocks."
Edd: "Tell me the truth, doctor. How long have I for this world?" Ed: "Um… till lunch?" [The camera zooms in, the background turns red, and Edd gets a horrified look on his face.]
Edd: "Oh, Double D, I knew thee well!" [runs away sobbing while Eddy is laughing at his own trick on Edd's "death"] Ed: [sobbing at Edd's "final" life]: "Poor Double D!" Eddy: "Double D ain't really sick, lummox! Remember?" Ed: [recalling that Edd isn't dying] "That's some good T.V. right there."
Edd: [furious with Ed and Eddy's prank on him] "ARE YOU PROUD OF YOURSELVES!?" Eddy: "Hang on there, Hamlet!" [He and Ed continue laughing at the brick wall they built around Kevin's house.] Ed: [talking about the brick wall and Kevin stuck inside] "Too rich, huh Double D?" Edd: "LISTEN TO ME!" Eddy: [stops laughing] "How can we not?" Edd: [showing the "Kick Me" sign that Eddy put on him earlier] "This was found on my body. YOU HAD ME BELIEVE I WAS EXPIRING!"
Ed: [in fear of seeing Kevin] "SPONGE STAMPEDE!" Kevin: "Get back here!" Ed & Eddy: "Kevin can't get us! Kevin can't get us!" Eddy: "Oh no, Ed! I'm so scared!" Ed: "I am shaking like cheese." [he and Eddy start laughing hysterically and continue to dance around, as Kevin grows angrier] Kevin: [growls and mumbles obscenities under his breath] Edd: [while holding Eddy's house keys] "Oh look, Eddy's spare house keys." [purposely drops them] "Oops. How careless of me. I must've misplaced them." [Kevin starts to smile and picks up the keys, while Eddy and Ed continue to laugh and dance, until Kevin joins them and panics Eddy.] Eddy: "NO! NOT THE FACE, KEV!" Edd: [reading happily from his medical book as the spectacle of Kevin working out his anger on his two friends goes on in the background] "Kevin's Justified Pummel Disorder – symptoms include bruising of the eye, followed by a sore rear end, and the rapid release of hot air from an inflated ego." [Edd laughs to himself.]
The pile of toilet paper rolls that Ed and Eddy were using to vandalize Kevin's house vanishes by the time of Jimmy and Edd's arrivals to the scene.
Ed was seen with four toes but most of the time all the characters have three toes.
Look closely: When Edd is giving his stuff to the kids you can see Nazz and Sarah with four toes.
Just after Edd was talking to Nazz and crying, if you look closely at Sarah in the close-up shot of her, she's wearing her normal pink shirt but in the next shot of her, she has her yellow swimsuit back on.
In the shot when Jimmy kicked Edd's buttocks, you'll notice Edd's got both his shoes. But in the next shot of his full body, both of his shoes are gone.
Despite it being blocked from viewers, this marks the second time Eddy shows his bare bottom to anyone. The first was in "Pop Goes the Ed." However, Eddy does this on purpose just to gross out Kevin.
Ed broke the fourth wall by saying, "That's some good T.V. right there."
The name "Cathro" from Lackadaisycathro Disease is derived from Ken Cathro, a worker on the show.
If you look closely during the scene where they show Kevin's room, you can see a poster that says "Bikini Babes" in his room. That name on the poster is similar to the magazine that Kevin reads.