This tune goes all the way back to at least World War II, folks. If the nuclear bomb and increased attacks against the Nazis hadn't worked, this song might have just confused our enemies to death.
It's been recorded many times. I like the Chet Atkins' version, even though his vocal range extended from A almost all the way over to A.1! He was still able to pull it off.
You know, it is obvious, hearing the tune, that it is an older one. The subject matter is that which you would never hear a rapper do. And, besides, the lyrics are clever, very clever; and they rhyme, too. Most songwriters today don't bother rhyming their lyrics.
I am including the Ray Stevens version because the absurdity of it all is not lost on him as he sings it. It is as if he is having a hard time believing it happened, even though (to the song's main character) it did.
Here it is, with a diagram to help you out: :"I'm My Own Grandpa".