This mushroom actually exists. The Latin name translates quite literally to “Shameless penis”. In English its common name is “Stinkhorn fungus”, and it has been described to me as a large, phallus-shaped, pallid, woodland fungus smelling very strongly of rotten meat, and usually covered with flies. “Once experienced, never forgotten”, as my source puts it.
Another mushroom expert subsequently mailed me a long, detailed description of the toadstool’s appearance, which I’m not going to include here. Suffice it to say that it’s full of phrases like “yellow, glutinous goo”, “the head exudes a black slime” and “I’ve smelled these from 50 paces on a still day”.
And no, the Phallus Impudicus is not edible.