畫蛇添足

lit. draw legs on a snake (idiom); fig. to ruin the effect by adding sth superfluous / to overdo it

variant of 蛇[she2]

snake / serpent / CL:條|条[tiao2]

excessive

foot / to be sufficient / ample

to add / to increase / to replenish

to draw / picture / painting / CL:幅[fu2],張|张[zhang1] / classifier for paintings etc / variant of 劃|划[hua4]