A couple of notes from an article that is really about a cooking trip to Lapland. Raindeer Games.
Santa and his flying reindeer were said to be inspired by shamanistic visions sparked by hallucinogenic mushrooms native to Lapland.
The original Finnish image of Father Christmas is positively frightening, he has the head of a goat, is hostile to children and demands gifts from them.
When Sami shamans enter a trance with the help of psychedelic mushrooms, their spirits leave their bodies, travel great distance, return home, fly down the chimney hole in the roof of their yurts. This may be the model for the story of Saint Nicholas.