Layer of Carceri
The fifth layer of Carceri is a realm where each orb is coated in a cold, shallow ocean fed by constant black snow. The snow and water are mildly acidic, automatically dealing 1d6 points of acid damage per 10 minutes of direct exposure. Artificial structures do not last long in Porphatys. Small islands barely taller than sandbars rise above the waves. Most petitioners crow from atop the small sandbar islands, promising anything to those who can take them away. Despite their entreaties, they reward any charity with betrayal at the first opportunity. Another exiled titan lives here, but even his palace is half sunken and slowly crumbling before the acidic waves.
Ship of One Hundred: A ship rides the cold swells of Porphatys's seas, called the Ship of One Hundred, though in some accounts it is referred to as the White Caravel. It appears as a ghost-white caravel unmanned by any visible crew. It wends between the islets of many orbs (somehow disappearing on one orb and appearing on another), picking up stranded souls and other travelers who are brave (or foolish) enough to brave passage. Passengers soon discover that apparently no one moves on board the craft. The lower deck and hold are stuffed with exactly one hundred unadorned stone sarcophagi. No one has ever successfully opened a sarcophagus and lived to tell the tale. Any time this has been tried, some unrecorded calamity devours all creatures currently on board, and the next time the ship puts in at a new port it is utterly empty of life. Stories have it that the ship seeks to deliver its terrible cargo, but it waits for the end times to do so. Between the “cleansings” that occur when the curious try to open a sarcophagus, travelers (mostly petitioners, demons, or other creatures) infest the ship. Some make it their temporary home, happy to move from place to place by whatever mysterious force steers the ship. These denizens take a very dim view of visitors who want to open a sarcophagus.