Chinese Idiom：草木皆兵 (cǎo mù jiē bīng)

In AD 383, the king of Former Qin (qín cháo 秦朝), Fu Jian (fú jiān 苻坚), led a huge army to attack Eastern Jin. After losing the first round of fighting, Fu Jian looked down from a city wall, and was terrified when he saw the formidable battle array of the Eastern Jin army. And then looking at the mountains around, he mistook the grass and trees for enemy soldiers. As a result, when the nervous Fu Jian led his army into battle, it suffered a crushing defeat.
This idiom describes how one can defeat oneself by imaging difficulties.

 

东晋时代，秦王苻坚控制了北部中国。公元383年，苻坚率领步兵、骑兵90万，攻打江南的晋朝。在淝水一带，被晋军出奇击败，损失惨重，大将被杀，士兵死伤万余。秦军的锐气大挫，军心动摇，士兵惊恐万状，纷纷逃跑。此时，苻坚在寿春城上望见晋军队伍严整，士气高昂，再北望八公山，只见山上一草一木都像晋军的士兵一样，于是更加恐慌。后来苻坚全军覆没，带着少数残余的队伍逃回去了。
这个成语后来形容人在极度惊恐时，疑神疑鬼的心理状态。

 

草木皆兵 (cǎo mù jiē bīng)
【翻译】Every bush and tree looks like an enemy.
【释义】把山上的草木都当做敌兵。形容人在惊慌时疑神疑鬼。
【例句】淝水之战中，苻坚先是盲目乐观轻敌，后是草木皆兵，自乱阵脚。
【近义词】杯弓蛇影
【反义词】若无其事、镇定自若