THE DUDE!
Your rye bread hosts ergot and your mind has entered witches realms.
What magical powers would you like:
Flight, telepathy, or precognition?
It started with bread.
In the Europe of the Middle Ages and into the Renaissance, bread was made, in large part, with rye. And rye and rye-like plants can host fungus—ergot*—that can, when consumed in high doses,
be lethal. In smaller doses, however, ergot can be a powerful hallucinogen. Records from the 14th to the 17th century mention Europeans' affliction with "
dancing mania," which found groups of people dancing through streets—often speaking nonsense and foaming at the mouth as they did so—until they collapsed from exhaustion. Those who experienced the "mania" would later describe the wild visions that accompanied it. (In the 20th century,
Albert Hofmann would realize the psychedelic effects of LSD
while studying ergot.)
So people, as people are wont to do, adapted this knowledge, figuring out ways to tame ergot, essentially, for hallucinatory purposes. And they experimented with other plants, as well.
Forbes's David Kroll
notes that there are also hallucinogenic chemicals in
Atropa belladonna (deadly nightshade),
Hyoscyamus niger (henbane),
Mandragora officinarum (mandrake), and
Datura stramonium (jimsonweed).
Writing in the 16th century, the Spanish court physician Andrés de Laguna
claimed to have taken "a pot full of a certain green ointment … composed of herbs such as hemlock, nightshade, henbane, and mandrake" from the home of a couple accused of witchcraft.
https://www.theatlantic.com/technology/archive/2013/10/why-do-witches-ride-brooms-nsfw/281037/
