Scatha the Worm - "Many lords and warriors, and many fair and valiant women, are named in the songs of Rohan that still remember the North.  Frumgar, they say, was the name of the chieftain who led his people to Éothéod.  Of his son, Fram, they say that he slew Scatha, the great dragon of Ered Mithrin, and the land had peace from the long-worms afterwards.  Thus Fram won great wealth, but was at feud with the Dwarves, who claimed the hoard of Scatha.  Fram would not yield them a penny, and sent to them instead the teeth of Scatha made into a necklace, saying "Jewels such as these you will not match in your treasuries, for they are hard to come by."  Some say the Dwarves slew Fram for the insult.  There was no great love between Éothéod and the Dwarves." ~The Return of the King (Appendix A)

"Then Éowyn gave to Merry an ancient horn, small but cunningly wrought all of fair silver with a baldric of green; and wrights had engraven upon it swift horsemen riding in a line that wound about it from the tip to the mouth; and there were set runes of great virtue.  'This is an heirloom of our house,' said Éowyn.  'It was made by the Dwarves, and came from the hoard of Scatha the Worm.  Eorl the Young brought it from the North.  He that blows it at need shall set fear in the hearts of his enemies and joy in the hearts of his friends, and they shall hear him and come to him.'" ~The Return of the King, Book VI, chap. 6 (Many Partings)