In ancient times, there was a man who raised monkeys, which became more and more mischievous as they grew up and often destroyed his things. One day the man caught a cock. He assembled the monkeys and said to them:” If you don’t behave and stop causing trouble, you will end up like the coke.” Then he killed the coke in front of the monkeys. Seeing this, the monkeys were frightened and became obedient thereafter.This idiom is used metaphorically to mean to frighten somebody by punishing someone else.

古时候，有个人养了一只猴子，这猴子可机灵了，他一听到鼓声就会跳舞，一听到锣声就会翻斤斗，可是就不听主人的指挥。耍猴戏的使劲打鼓，使劲敲锣，猴子眨眨眼睛，一动也不动。这个人想了个办法，他抓了一只公鸡来，然后拿起一把刀，当着猴子的面把公鸡杀了。这一下可把猴子吓坏了。耍猴戏的一打鼓，他就连忙跳舞，一敲锣，他就连忙翻斤斗，变得非常老实。这个成语比喻惩罚一个不相干的人，来威胁另一个人。

杀鸡吓猴 (shā jī xià hóu)
【翻译】Kill the Chicken to Frighten the Monkey.
【释义】杀鸡给猴子看。比喻用惩罚一个人的办法来警告别的人。
【例句】Tom犯了错，老板怕其他员工犯同样的错，于是杀鸡吓猴，扣了Tom一个月的薪水。
【近义词】杀一儆百、杀鸡儆猴
【反义词】既往不咎、宽大为怀