I hate to be a party pooper, but I am really tired.

我真不想扫大家的兴，不过我真的太累了。

《柯林斯英汉双解大词典》

I am not going to be the only party pooper here.

我才不要作为这里唯一的扫把星。

youdao

There is a similar phrase — party pooper.

Party pooper是在派对上扫大家兴的人！

youdao

Despite urgings by all not to be a party-pooper at Oslo, Mr Arafat could not entirely suppress his frustration.

ECONOMIST: Israel and the Palestinians

In Britain, a doggy bag can be confused with a pooper-scooper, which deals with a different kind of waste altogether.

BBC: Doggy bag: Why are the British too embarrassed to ask?

Nonetheless, the Fed continued to play the party-pooper this week, raising rates by another quarter of a percentage point, to 3.75%, at its meeting on Tuesday September 20th.

ECONOMIST: Reluctant party-poopers | The