Very interesting 🤔 Here is some information.Despite its easily distinguishable features, A. muscaria is a fungus with several known variations, or subspecies. These subspecies are slightly different, some having yellow or white caps, but are all usually called fly agarics, most often recognizable by their notable white spots. Recent DNA fungi research, however, has shown that some mushrooms called 'fly agaric' are in fact unique species, such as A. persicina (the peach-colored fly agaric).

Native throughout the temperate and boreal regions of the Northern Hemisphere, A. muscaria has been unintentionally introduced to many countries in the Southern Hemisphere, generally as a symbiont with pine and birch plantations, and is now a true cosmopolitan species. It associates with various deciduous and coniferous trees.

Although poisonous, death due to poisoning from A. muscaria ingestion is quite rare. Parboiling twice with water weakens its toxicity and breaks down the mushroom's psychoactive substances; it is eaten in parts of Europe, Asia, and North America. All A. muscaria varieties, but in particular A. muscaria var. muscaria, are noted for their hallucinogenic properties, with the main psychoactive constituents being muscimol and its neurotoxic precursor ibotenic acid. A local variety of the mushroom was used as an intoxicant and entheogen by the indigenous peoples of Siberia.

Arguably the most iconic toadstool species, the fly agaric is one of the most recognizable and widely encountered in popular culture, including in video games—for example, the frequent use of a recognizable A. muscaria in the Mario franchise (e.g. its Super Mushroom power-up)—and television—for example, the houses in The Smurfs franchise. There have been cases of children admitted to hospitals after consuming this poisonous mushroom; the children may have been attracted to it because of its pop-culture associations.

Also the thesis about the connection to Santa Claus and the red and white colours.

Also: Shamans' psychotropic journeys are believed to be related to the idea that Santa Claus travels with his sleigh and reindeer through the skies to deliver gifts. The gift given by the shamans was the knowledge that the mushroom gave them, in addition to sharing portions of it among those present.