There’s the mushroom theory.
that Santa brought amanita muscaria mushrooms as gifts to families which are poisonous but poisonous like alcohol is poisonous. They get you fucked up. Not like trippy psilocybin mushrooms but u get real loosey goosey and energetic. Reindeer are known to eat them and jump up into the air. They’re red mushrooms w/white spots, like the Mario mushrooms. Supposedly Santa gets the colors of his outfit from the mushroom.