Rare Exports: A Christmas Tale is a 2010 award-winning Finnish movie, a dark fantasy/horror film described by Wikipedia as being "about people living near the Korvatunturi mountain who discover the secret behind Santa Claus". This is fascinating! You can watch it free on Tubi.
The New York Times says this movie is "as black as anything the Brothers Grimm could have dreamed up" and says, "adults will enjoy the exuberantly pagan images and deadpan humor." The Guardian concludes, "Intriguing fun and very resourceful."
Empire Online says, "this offers very black humour and a strange mix of revisionist mythology, gruesome horror and authentic Christmas spirit." io9 calls it, "the most disturbingly awesome Christmas movie ever".
Roger Ebert gives it 3.5 out of 4 stars. Rotten Tomatoes has a critics rating of 89%.