“脑子进水了”我们常见的是：Are you out of your mind? 你脑子进水/秀逗了？此外美国还有一个非常贴切但比较粗俗的俚语：have shit for brains，means to be very stupid，例如：What the hell are you talking about, Terry? You've got shit for brains. 你他妈在说什么啊Terry？你脑子进水了吧！
气急时可以再加个词增强语气：Are you out of your freaking mind? 你特么脑子进屎了么？
I got it