In "Journey to the West", the monkey king Sun Wukong obtained his "Ruyi Jingu Bang", a magically-expanding, gold-ringed iron rod weapon, from Ao Guang. This weapon was originally a tool for measuring the depth of sea water used by Yu the Great in his flood control and treatment efforts; hence its ability to vary its shape and length. After Yu left, it remained in the sea and became the "Pillar holding down the sea", an unmovable treasure of the undersea palace of Ao Guang.