Stern poetic justice shall be meted to those who would deny the existence of Santa Claus:

In Baltimore there lived a boy, / He wasn't anybody's joy.
Although his name was Jabez Dawes, / His character was full of flaws.
In school he never led his classes, / He hid old ladies' reading glasses,
His mouth was open when he chewed, / And elbows to the table glued.
He stole the milk of hungry kittens, / And walked through doors marked No Admittance.

He said he acted thus because / There wasn't any Santa Claus.
...
Yet people pardoned every sin, / And viewed his antics with a grin,
Till they were told by Jabez Dawes, / "There isn't any Santa Claus!"

http://www.huumor.com/article.php?sid=15 tells the full story of Jabez's horrible fate.