Suspicion breeds phantoms - every tree and blade looks like an enemy.
Tips
history
From the 《晋书·苻坚载记》: Fu Jian, emperor of Former Qin, watched the Jin army at the Battle of Fei River (383 CE) and became convinced that every tree on Mount Bagong was an enemy soldier. His panic contributed to one of China's most famous military upsets.
culture
Same historical event gave us 风声鹤唳 ('even the wind and cranes sounded like enemies') - often paired with 草木皆兵.