The following seems to be based on an old-time or bluegrass song, but I don't have any information about the original.

Lyrics transcribed from the sound file at http://www.geocities.com/u2page6/

THEY LAID HIM IN THE GROUND
(As sung by Homer & Jethro)

CHORUS: They laid him in the ground, boys, laid him in the ground.
One more there an' one less here. They laid him in the ground.

Once I had a Thomas cat. He could warble like Caruso.
A neighbor swung a baseball bat. Now Thomas doesn't do so. CHORUS

Now Uncle Henry learned to fly a plane up in the air.
His parachute was full o' holes, but Henry didn't care. CHORUS

A man stood on a divin' board. He made a monstrous leap.
He didn't know the water there was only one foot deep. CHORUS

Now Mr. Julius Caesar was a great man, we all allow.
The greatest man of all his day, but where is Caesar now? CHORUS