In the Silmarillion, the universe was created by the music of the Ainur. At first it was in line with the mind of Iluvatar (God) but Melkor sang louder and then in discord. Some fans theorize that this discord created Tom Bombadil, along with barrow wrights, Shelob, the watcher of the water, and the ancient creatures that Gandalf saw while chasing the Balrog under Moria.