Treasure beach

On the other side of the torrent's mouth, barely visible in the darkness. Large green mushrooms everywhere. A treasure cache containing the result of decades of hard piracy labor, under a trapdoor hidden under the sand.

→ Mushrooms. Used for Zénopuce's potions. Breath the spores: CON check or fall in a nightmare filled sleep for d4 hours.
→ Cache. A natural cavity contains a god-king's ransom (250,000 gp in ingots, jewelry, and coins) and a spooky altar. Would need five oxcarts to carry.
→ Altar. Made of fused humanoid bones and dedicated to the Black Flag Saint, a minor god of pirates. Protects the treasure from thieves: a non-pirate taking but a silver piece gets a black mark in the shape of a skull on the back of their left hand (or corresponding appendage). Any rogue, thief, or privateer is duty bound to make such a traitor pay.