Scatha also known as Scatha the Worm, was a mighty Long-worm of the Grey Mountains and one of the greatest Dragons to infest the them of the north. Little is known of Scatha's life, except that he was slain by Fram son of Frumgar (an ancestor of Eorl the Young) in the early days of the Éothéod.
His recovered hoard was the subject of great dispute between the Men of the Éothéod and the Dwarves of that region, who claimed the hoard as their own. Fram rebuked their claim, and sent them the teeth of the dragon, with the words, "Jewels such as these you will not match in your treasuries, for they are hard to come by." Thereafter there was war between the Éothéod and the Dwarves, a war in which Fram met his end.
However this dispute was resolved (we are not told), it seems that Fram's people retained at least some of the hoard, and brought it south with them when they settled in Rohan. The horn that Éowyn gave to Merry Brandybuck after the War of the Ring many hundred of years later was said to come from it.