画蛇添足huà shé tiān zú

What does 画蛇添足 mean?

Draw legs on a snake — ruin what's already done by adding what was never needed

比bǐ喻yù做zuò事shì已yǐ经jīng很hěn好hǎo了le，却què多duō此cǐ一yì举jǔ，反fǎn而ér把bǎ事shì情qíng弄nòng坏huài了le。

Historical origin

In the state of Chu, after a ceremony, a lord placed one bronze pot of wine in the centre of the courtyard for his servants. They agreed that whoever finished drawing a snake first would win it. A-Sheng completed his snake before the others and picked up the pot to claim it, but then proudly began adding six legs to his snake. Meanwhile, A-Hui had not yet finished her snake, but while A-Sheng was busy adding the legs, she completed hers, took the pot from him, and reminded him that snakes have no legs — so his 'snake with six legs' was no snake at all, and the wine was rightfully hers.