"‘This is Sting,’ he said, and thrust it with little effort deep into a wooden beam."
Sting is an elf-blade that was found in the horde of the trolls that tried to eat Bilbo and the dwarves in The Hobbit
. It glows blue in the presence of orcs. Sting is actually a knife, but works as a sword for a hobbit. It was found with two longer swords, Glamdring and Orcrist. Thorin, leader of the dwarves, took Orcrist and Gandalf took the sword Glamdring, which he carries with him in The Lord of the Rings