Actually National Geographic made a film of some reindeer eating this mushroom ~ looks like their eyes are spinning too. Human beings who eat the mushroom (or drink the properly flavored urine) develop a perception of flying.
Again, the whole Santa Claus, his sleigh, his reindeer, his bag of gifts, climbing down the chimney (or through the smoke hole in the tent) ~ all that stuff is there in the ancient stories of the far North.
"He used ta give a little bit to da reindeer, a little bit to Santa Claus, a little bit more for Santa Claus, a little bit more..."