A house-elf who was utterly devoted to Harry Potter, Dobby put himself at great risk (and in serious physical pain) when he went out of his way to protect the young wizard from what Dobby knew would be significant danger. His loyalty and bravery were rewarded eventually, as he was freed from his cruel wizarding family with a gratefully received dirty sock. Harry and Dobby became firm friends after that and more socks would come into Dobby's life.