Well of Souls

The Well of Souls was a mythical treasure that turned out to be cursed and sealed. When the mortal captain tried to claim it, it claimed him instead; the captain became bound to the Well of Souls and then subjugated it, so that the Well of Souls became a ship with the captain as its helmsman. Although they never reached the Eternal City, they were cursed to wander the Stormsea forever. The Dutchman was described as a kind of well of souls and a nesting doll of horror: the ship consumes souls and enslaves them, sends them out to slaughter the living and conquer more souls, and when its wraiths are slain they are not destroyed but sent back into the holds of the smaller ships, while destroying those ships simply returns them to the Dutchman. Once it gets you, there is no escape.