What happened to gulliver while he slept after being ship wrecked?

While Gulliver slept, his "Arms and Legs were strongly fastened on each side to the Ground; and [his] Hair, which was long and thick, tied down in the same manner." He feels something moving along his body almost up to his chin, at which point he sees that it is "a human Creature not six Inches high, with a Bow and Arrow in his Hands, and a Quiver at his Back."