During the Spring and Autumn Period, King Ping of Chu executed Wu Zixu's father and elder brother. Fleeing to the State of Wu, Wu Zixu swore to destroy Chu and avenge his family. His close friend Shen Baoxu urged him not to betray his homeland for personal revenge, but Wu Zixu refused to listen. Shen Baoxu then declared, "If you insist on destroying Chu, then I swear I will restore it!" With that, the two severed their friendship forever.
Later, Wu Zixu arrived in the state of Wu, where he first helped Prince Guang seize power and become King Helü of Wu. He then urged the king to take advantage of the political chaos in Chu and launch a military campaign, successfully breaching the Chu capital, Ying. By then, King Ping of Chu had already died, and his son, King Zhao, fled in panic. Wu Zixu exhumed King Ping's corpse and flogged it three hundred times in vengeance.
When Shen Baoxu saw Wu Zixu's actions, he was deeply outraged. He went to King Zhao of Chu to discuss plans for restoring the kingdom. However, Chu was now too weak to act alone and needed help from a neighboring state. Shen Baoxu argued for seeking aid from Qin, reasoning, "King Ping of Chu's wife was the daughter of Duke Ai of Qin, making King Zhao of Chu the duke's nephew."
King Zhao of Chu agreed with Shen Baoxu's proposal and dispatched him as a special envoy to the state of Qin. Upon meeting Duke Ai of Qin, Shen Baoxu urgently laid out Chu's dire situation and Wu's brutal aggression, describing Wu as a "giant boar and venomous serpent" whose insatiable greed would, after devouring Chu, inevitably threaten the Central Plains and endanger Qin itself. He argued that Qin should dispatch troops swiftly to help restore Chu, which would also serve Qin's own security.
Later, with the aid of the Qin state, Chu managed to reclaim all its lost territories and gradually restored its status as a powerful kingdom.
"Feng Shi Chang She" (Huge Boar and Giant Serpent) refers to legendary ancient beasts of great evil and poison.
Later, the idiom "Feng Shi Chang She" came to describe greedy and violent people.
Source: *Zuo Zhuan*, "Duke Ding, Fourth Year"
Meaning of the Idiom: Later, the Chinese idiom "封豕长蛇" came to describe greedy and violent people.