speak of the devil
说到曹操，曹操就到
口语·调侃某人突然出现
英文释义
to mention someone who then appears unexpectedly
例句
Speak of the devil, here comes Tom right when we were talking about him.
典故来源
源自西方古老迷信，认为提及魔鬼名字会招来它，后演变为指被谈论者突然出现。