The serpent Sword of Elmerillion has been fabled in Goblin Folklore Tales ever since it was first fabled in them.
It was forged by the Great Elf - the Blacksmith Elf - the Maker-of-Nails - the White Wizard of the Elfin Mire - who gave it as his only weapon to Loph, the Garter Goblin, to fight his duel with Isk, the Grey-Legged Wanderer from the Murks of Thell. The Serpent Sword of Elmerillion proved its worth at once in that dreadful encounter, and ever after it has come to be a goblin byword for a absolute uselessness. Loph was killed instantly before he could even lift the cumbersome Serpent Sword, and Isk, the Grey-Legged Wanderer, turned on his heel and wandered back to the Murks of Thell, laghing to himself, and eating slices of Grit Cake. The Great Elf - the Blacksmith Elf - the Maker-of-Nails - the White Wizard of the Elfin Mire never made another sword after that, and the Serpent Sword of Emerillion was hung in the Great Hall of Unconventional and Useless Objects, in between the Giant Hairy Pin and the Unwarmable Rat-Tickling Device.