The ferocious God of Thunder was captured by Fuxi's father and imprisoned deep within a mountain cave. No one was allowed to visit him. Fuxi and Nüwa could no longer bear to hear the Thunder God's pitiable entreaties for water, but they dared not bring him any water. Eventually, the two of them shed tears which the god drank out of their cupped hands. The Thunder God was so strengthened by the tears that he burst out of his mountain prison. To repay Fuxi and Nuwa for their part in the rescue, the Thunder God pulled a long canine tooth from his mouth and gave it to them saying:
"In three days, mankind will suffer a terrible calamity. You may use this tooth to keep yourselves safe from harm."
Having said this, the Thunder God leaped into the sky and disappeared.