Once every decade on the eve of St. Poskov's Day during mid-winter, the coastal city of Tiyabon experiences a horrific event. Quool's Tide rolls in, depositing hundreds of bloated, fish-eaten corpses upon the pebbly shores of Tiyabon's wide bay. This singularity is to this day unexplained, though countless theories abound. It is said for example, that these corpses are not eaten by the myriad fish of the seas completely, due to the fear all creatures of the seas hold for Quool.
Named for Quool, a terrible, antediluvian god of seas and storms, who no longer exists for he has no worshipers, the Tide chokes the beaches and surf with the countless rotting bodies of those who had perished at sea in a violent way.
Almost immediately, the lifeless corpses are fed upon by crabs, gulls, and worse things that await the horrid feast. The townsfolk let nature take it course with disinterested disgust, though lately some enterprising adventurers have taken to searching along the beaches of flesh for former deceased companions, with intentions of raising them again!
Surprisingly no undead ever rise from among the many corpses. This is also a mystery.
In the harbour of a major city a large and terrifying ship made of human nails docks. Nobody seems to inhabit this ominous vessel, someone needs to go on board and unveil the mystery. In comes the PCs.
Stormbound, the ship rolls hard over to once side. All that is not strapped down is tossed violently overboard in a splash of freezing water.
There, on the horizon- a tower. Squat, it stands alone on a tiny island. However, it's the only land in sight, and any more of this ferocious storm will crush the boat to splinters.
Taking shelter within the ornate entryway of the squat tor, the party notes with interest that no signs of life break the silence of the stone tower. As they take another step forward, they realise why.
This is the fabled tower of Brenji, a rich merchant who wished none to share his enormous wealth. He constructed this tower to store his gold- trapped and ready for any potential thieves. But the ingenious pitfalls and scything walls are not the only dangers within the silent walls of the building. A guardian, left behind by Brenji, still stalks these very halls.
A rattling hiss echoes somewhere from below...
You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)