banana skin
noun [ C ] UK informal uk/bəˈnɑː.nə ˌskɪn/ us/bəˈnæn.ə ˌskɪn/
使人出丑（或引起麻烦）的突发事件
a sudden unexpected situation that makes a person appear silly or causes them difficulty
The new tax has proved to be a banana skin for the government. 事实证明，新税收给政府带来了麻烦。