That would be to throw someone a curve ball, to confuse them or to give them something that's unexpected.

那就是向某人抛出曲线球，让他们感到困惑或给他们一些意想不到的东西。

The expression, to throw someone a curve ball, means to give them something unexpected, something that they didn't think would happen that causes you problems or causes you trouble.

表达，to throw someone a curve ball， 意思是给他们一些意想不到的东西，一些他们认为不会发生的事情会给你带来麻烦或给你带来麻烦。