The Haunted Doctor shrinks from a sorrow-spider

 is a Sunless Sea Story Event.

Story description
"How did that horrible creature get aboard the ship?"

Trigger conditions
The event triggers soon after you have the following:

Learning About: The Haunted Doctor = 3 [ You have wined the Haunted Doctor ] Saviour's Rocks: Caught in the webs of Saviour's Rocks ≥ 1, which can be activated by participating in Preparing for the Festival of Silk at  Saviour's Rocks.

Random Chance: 100%