With regard to the plot "Sleeping Mines of Elathon":
You manage to get the water wheel in the mine working which operates a pump to clear the flooded lower levels. As you explore the dank tunnels of the lower galleries, you can hear the creaking of the wheel above. You enter a low-ceilinged passage and are crawling on your backs, when the creaking stops. The water starts seeping wetly around the back of your head...
A race of halflings has lived so long underground that their skin has taken on the color and texture of cauliflower, they are called the Cauliflower or the Mushroom People for their skin and aversion to light.