"Maybe the neighbors upstairs spilled something?"
"Or has something... organic appeared in the ceiling?"
mushroom manure1
It turned out to be neither. It was a mushroom. A real one, with a thin, curved stump and a gloomy cap. And not just any mushroom—but Coprinopsis atramentaria , known among the people as the “ink mushroom” or “dung mushroom.”
Yes, you're right — a fungus grew from my ceiling, which usually grows on manure, rotting plants, or in very moist soil.
What's so scary about this mushroom?
The plant itself is not poisonous — until it is combined with alcohol. Even up to 3 days after its consumption, if alcohol is consumed, severe poisoning can follow: nausea, vomiting, tachycardia, feeling of heat, anxiety.