The Hypo-Chondri-Cat is a Merrie Melodies short, released in 1950.
Bert and Hubie help themselves to a warm fire and some cheese in their new home, until they encounter Claude Cat. A chase then ensues, but Claude freezes up before he passes an open window. Fearing he might catch pneumonia, he pops pills and takes his temperature. Realizing he's a hypochondriac, both mice play up on this by suggesting Claude is turning himself all sorts of colors (including tartan!) before dismissing him as a hopeless case. Claude breaks down and persuades the mice to save his life.
Claude ends up in an operating theatre, where the mice prepare a fake operation by slicing up some cheese. Believing them to be operating on himself, Claude passes out in "pain" and goes into a surrealistic nightmare.
Claude reawakens, not realizing he's wearing a white gown and fake wings. He sees Bert and Hubie crying over his grave, and the pair are in "shock" when they see him as a "ghost". With the aid of an x-ray machine, he believes them and begs again for their help. They lead him to a cliff with a sign pointing to "cat Heaven," but despite him saying he can't fly, they shove him off the cliff. Claude does fly, but he doesn't realize that they tied a helium balloon to his back. "Farewell, you poor earthly creatures", says Claude to the mischievous rodents as he flies towards the moon.
On ABC the part where Hubie slaps Bertie several times is shortened.
According to the storyboard (included as a bonus feature on the Looney Tunes Golden Collection Volume 1 DVD set), this cartoon originally was to have had one more scene at the end, which didn't appear in the final cut of the cartoon; As Claude Cat floats via balloon to "Cat Heaven," Hubie and Bertie are shown inside the house, in front of the fireplace, roasting cheese clumps (shaped like marshmallows) on toothpicks. Claude is seen through the window, blissfully drifting skyward.