Going back through history it is evident that religions and religious holidays are built from or borrow from even older ancient roots. Pre Christianity pagan religious beliefs were dominant in those times. So what do magic mushrooms have to do with Christmas you may ask?
Santa Claus or Saint Nicholas is just the modern westernized version of ancient shamans who would celebrate the winter solstice, often by bringing hallucinogenic mushrooms as gifts to other members of the group or tribes. In Northern Europe and in the Siberia area winters are long and cold and resources can be hard to come by. The people of the times would notice reindeer grazing through the snow and often under pine trees and would hunt for the (Amanita Muscaria) mushrooms which are a bright red color with white polka dot like patterns.
Shamans would collect the magic mushrooms from under the pine trees and etc then dry them often by hanging on the pine trees themselves. To celebrate the winter solstice and being halfway through the winter shamans would deliver bags of the hallucinogenic mushrooms through the chimney or hole in roof of the teepee like homes of The tribes people. Usually because the main door or entrance would be blocked by snow. It's not hard to start seeing many simularities from the red and white gifts under the trees to hanging the red and white mushrooms on the trees and a cloaked gift giver from the arctic delivering gifts throught the chimney.
Through the millennia, centuries and the addition of christianity and other influences the roots of Christmas reach far back into ancient times. It's an interesting thing to research if you are interested just google magic mushrooms and Christmas.