The Derelict (Unabridged‪)‬

The sea is a lonely place, particularly when your ship was blown off course and disabled. William Hope Hodgson takes this scenario and adds the discovery of a derelict ship floating near you. Of course you would go investigate, wouldn't you? The captain and part of the crew - including the ship's doctor, who is telling the story - visit this enticing phantom. They find the ship inhabited by a living mold that had been lying dormant just waiting for its next meal.