Santa (Krampus) is coming to town

You better watch out, You better not cry, Better not pout, I'm telling you why: Santa Claus is coming to town. He's making a list, And checking it twice; Gonna find out Who's naughty and nice. Santa Claus is coming to town.

He sees you when you're sleeping. He knows when you're awake. He knows if you've been bad or good, So be good for goodness sake! Oh, you better watch out! You better not cry. Better not pout, I'm telling you why: Santa Claus is coming to town. Santa Claus is coming to town!

I always wondered.  Why is santa claus coming to town? What is he going to do when he gets here?  Why is he watching me sleep?  And what happens when I'm naughty.?  IF I was told the krampus story I think I would have understood more fully what happens to naughty boys.