(the) shit hits the fan
US /ðə ʃɪt hɪts ðə fæn/
UK /ðə ʃɪt hɪts ðə fæn/

1.
事情变得一团糟, 爆发大麻烦
a situation when a problem or crisis becomes public and causes a lot of trouble or anger
:
•
When the news of the scandal broke, the shit hit the fan.
当丑闻曝光时,事情就变得一团糟。
•
He knew that if his boss found out, the shit would hit the fan.
他知道如果老板发现了,事情就会变得一团糟。