Something a friend came up with. Also, the image was found online.

Little clown of Gotham, why are you so sad?
Mommy went to find a bat and daddy's not that bad.

And yet you cry upon the sight
Of Gotham's king of comedy night.

Oh little clown of Gotham, tell me why you're sad
When mommy's helping daddy so life isn't so bad.

Little clown of Gotham, please show me a smile
Mommy's coming home tonight after hunting for a while

So come on and show some cheer
While Daddy smiles here

Little clown of Gotham, tell me why you frown
So I can cheer you up again and turn it upside-down

Little clown of Gotham, stay with Daddy dear
So Mommy doesn't need to worry or feel any fear

So please show me a happy face
And stay here in this place

Little clown of Gotham, tell me why you fear
Whenever daddy comes to play and stay so very dear.