哦，您原来跟齐天大圣一个姓埃我爸差点晕倒。。 I found this on http://m.zol.com.cn/xiaohua/detail45/44743.html.
The real name of 齐天大圣 is 孙悟空 (one of the major characters in 西游记) so its family name is 孙, but the patient misinterpreted, he think his family name is齐.
Maybe I could translate it in EN:
My father is a doctor. Once he met a patient.
The patient: "What's your name, sir?"(very formal/serious tone)
My father: "My family name is 齐(qi)" (We won't call one's first name if we're not familiar to him in general for regard)
The patient: "Wow, your family name is the same as 齐(qi)天(tian)大(da)圣(sheng)'s!"(surprised tone)
My father nearly passed out at that time.