“Santa is a modern counterpart of a shaman, who consumed mind-altering plants and fungi to commune with the spirit world,” said John Rush, an anthropologist and instructor at Sierra College in Rocklin, Calif.

According to the theory, the legend of Santa derives from shamans in the Siberian and Arctic regions who dropped into locals’ teepeelike homes with a bag full of hallucinatory mushrooms as presents in late December, Rush said.

“As the story goes, up until a few hundred years ago these practicing shamans or priests connected to the older traditions would collect Amanita muscaria (the Holy Mushroom), dry them, and then give them as gifts on the winter solstice,” Rush told LiveScience. “Because snow is usually blocking doors, there was an opening in the roof through which people entered and exited, thus the chimney story.”