Do you know the mushroom man,
The mushroom man, the mushroom man;
Do you know the mushroom man,
He lives beside the road.
Finding the mushroom man in Palenque isn't very hard. All you have to do is walk down the road for a bit — from El Panchán to the ruins — and he pops out of the jungle when he sees you. It's a hilarious setup: he's obviously keeping out of sight of the police — because he's selling illegal hallucinogenic mushrooms — but he's also obviously got some sort of "arrangement", because he's always there, and he's only really making a token effort to keep hidden.
I ran into the mushroom man a few times, when I was walking to the mystic waterfalls and back. He's a really nice guy, very friendly — about as far removed as you can get from the stereotypical, violent, threatening, hardened Western drug dealer. It's quite surreal, to just stop and have a pleasant roadside chat with someone in that line of business. He acts more like what he really is: a greengrocer.