The one where 'he won't come if you don't behave/ he sees you when you're sleeping/ he's making a list and checking it twice'?
Well, forget it.
Because this Christmas, there's a whole new humbug with which to threaten your kids.
And it's not Ebenezer Scrooge or the Grinch or the guy who makes the Snowman melt at the end every single year.
Top of the grumpy list for 2012 is none other than the Bishop of Rome, Vicar of Christ, Successor of the Prince of the Apostles etc etc. It's Il Papa.
Coming in 32 sleeps is Christmas 2012.
Just not as we've grown to know and love it as the Supreme Pontiff's writings have revealed.
With a new book to flog, Pope Benedict has been busy whipping up some publicity to give sales a push on his upcoming bestseller, 'Jesus of Nazareth – the Infancy Narratives', which sounds like a brilliant mash-up between a Dan Brown and 'Look Who's Talking'. Makes me all excited for possible sequels – 'The Secret Diary of Jesus of Nazareth' or 'Jesus of Nazareth – The Edge of Reason'.
Instead of jumping in his popemobile, however, and booking himself on the Toy Show, he's gone down the teaser route, releasing enticing little snippets of the content.
Thereby shattering little children's hearts with every flourish of his Popely quill.
Talk about Urbi et Scorpy.
Bombshell Number One There were no donkeys, oxen, calves, asses, dogs, cats, goldfish or, indeed, any other beasts, in the stable in Bethlehem. What? Not even a teeny weeny lickle lamb? Apparently not. It's a myth, the idea planted in our heads by pre-Christian traditions and writings like that ludicrous 'Book of Habakkuk', apparently, written by an early prophet in the seventh century BC.
Bombshell Number Two Carol singers, it appears, are the result of a terrible misunderstanding. All this time we've been belting out that 'Joy to the World' to commemorate the birth of Jesus in imitation of the heavenly hosts who announced the virgin birth.
We've been shockingly misled, however.
The angels never actually sang all that 'Glory to the Newborn King' stuff to the sleepy shepherds.
They just said it.
The most earth-shattering revelation, however, comes with the fact – brace yourselves – that Jesus most likely wasn't born on December 25 and possibly not in year 1.
Apparently, he arrived at some stage between 7 and 2BC.
Although we can't be too sure of that either.
So therefore, Christ was born Before Himself. And the whole sorry mess is the fault of some bloke called Dennis the Small in the 6th century who got his dates mixed up.
Forget the Budget.
2012 is shaping up to be the year that the Pope Stole Christmas.
It might work to the advantage of some, of course.
Nativity play cast cuts will give Mary and Joseph a lot more room to work the stage; the lack of lowing as the baby awakes leaves plenty of time for more sharp dialogue from the angels and the Moving Crib might be disappointingly static, but won't need as much straw.
On the downside however, we have absolutely no idea how many shopping days are left.
Well thank you very much, Dennis the Small. I don't see you worrying about the queues at Argos.
But it's frankly a relief to finally be sure that there were definitely no camels in that stable somewhere in the Middle East, possibly at some time during the reign of the Emperor Tiberius.
And good to know also that it's an unequivocal fact that a teenager was made pregnant by a ghost and gave birth to the son of God.
The Pope's observations on dates, times, eras, emperors and livestock – or lack of – aren't really relevant.
Nor are they the slightest discouragement to celebrate the coming festive season in what could be called a secular fashion.
Taking time out, spending it with loved ones, sharing appreciative tokens, giving thanks for blessings and being charitable and generous of spirit.
Or even teaching our kids to believe that a kind man they can't see will reward them if they are good.