螳螂捕蟬
táng láng bǔ chán
Literal: The Praying Mantis (螳螂, táng láng) hunts (捕, bǔ) the Cicada (蟬, chán)
Actual: Lack of foresight, inability to see the bigger picture
During the Spring and Autumn period, King Helu of the Wu Kingdom wanted to attack the Chu Kingdom. Why would anyone do that, Chu ask? Wu knows, really? In any case Helu sat on his throne and proclaimed, “I want to attack the Chu, and I will promptly execute anyone who objects. Does anyone object?” Nobody did. All the king’s men bowed their heads; they preferred keeping those on their necks. “Well then! Let us sortie.”
A young scholar in court bowed as well, but he was rather distraught. The scholar disliked both war and decapitation, so he came up with a plan. He starting walking around with a slingshot in his hand, as well as visibly wet sleeves on his scholarly robes. This continued for three days straight until the king finally flagged him down and asked: “Why don’t you get a change of clothes? We offer free laundry service - didn’t you attend orientation?”
The scholar stopped smiled. “Well you see, I’ve been hanging around the royal gardens recently. One day, I saw a cicada buzzing peacefully on a tree. However, a few inches away, a praying mantis was carefully stalking the cicada, readying its pincers and going in for the kill. Oddly enough, a few feet away on another branch perched a Yellow Siskin, about to spread its wings and swoop in for the mantis. I whipped out my trusty slingshot to get a shot at the bird - but alas, I accidentally fell into the garden pool instead. I suppose we can all afford to look before we leap, can’t we?”
The king gently smiled. “I see - I suppose you might be correct.” He soon called off the invasion and thus a war was avoided. The scholar was, to his relief, not decapitated (although he was put on laundry duty for a few weeks).
Extra credit - this Chengyu has several different variants. The source for this variant is here, in an ancient work of similarly proverbial stories (this took an hour to look up).
TL;DR: King is convinced to not act in haste by a scholar who tells a funny story. We could all do with more caution in our lives, lest we overlook the danger of praying mantises, decorative garden pools and overly eager grandparents who ask about your love life.