During the Warring States period, a nobleman in the state of Chu, after offering sacrifices to his ancestors, gave a jug of ceremonial wine to his attendants. They looked at the wine and saw it was too little for all. One of them proposed, "If we each drink from this jug, we'll only get a sip. Better to let just one person have it all—what do you think?"
Although everyone agreed, they could not decide who should drink the wine because no one was willing to yield. So, the one who first proposed it said, "Let's compete by drawing snakes on the ground. Whoever finishes first will be the owner of this wine. Agreed?"
Everyone agreed it was a great idea, so they set to work drawing snakes on the ground. One man finished quickly and was about to grab the wine jug when he saw the others still frantically sketching. Smugly, he held the jug in his left hand and continued drawing with his right, boasting, "Look, I can even add feet to my snake!"
"But just as he was drawing the feet, another person had already finished the snake. That person immediately snatched the jug of wine and said bluntly, 'Snakes never have feet—how could you add feet to one?'"
Then, raising his wine jug, he drank with great satisfaction, while the man who had originally added feet to the snake could only swallow his saliva in bitter regret from the sidelines.
Later, the idiom "drawing a snake and adding feet" came to be used to describe doing something superfluous that only makes things worse.
Source: *Strategies of the Warring States*, Chapter "Strategies of Qi II"
Meaning of the Idiom: Later, the Chinese idiom "画蛇添足" came to describe how doing something superfluous that only makes things worse.