This mountain chain was once vast and impenetrable, but had the misfortune to named in the binding spell of a mighty demonic(godly?) being, namely that when the Great Mountains are forgotten, then shall it be free.
On the road you meet… a fiery fire dragon! The mighty Xeatoxx is not some random encounter without purpose. He, though he is the last to admit, has a serious problem.
The heroes find a small crypt somewhere and being brave adventurers they want to check it for evil forces (=graverobbing). Or for any other reason.
If thrown into a moat or a ditch, they react with water to make an area of ground a foot wide and solid enough to walk on rise from the bottom. If eaten-well, the body of the one who ate one of them is a real mess. Used to storm moats and forge rivers, streams and ditches. Must be kept dry until used.