A couple of harsh sentences from an old friend act like a needle in a balloon causing the air inside gush out at a great speed.

一个老朋友几句刻薄的话，就象一根针刺到了气球上，导致里面的空气迅速的排出。

youdao

This may sound a bit like a needle-in-a-haystack problem. There are in many cases millions of bytes of data in a single running program.

这听起来有点像大海捞针，在一个单独运行的程序里有成千上万字节的数据，漫无目的的在数据海洋里乱找结果不会很理想。

youdao

Searching for one man in this city is like looking for a needle in a haystack.

在这个城市里找一个人无异于大海捞针。

《牛津词典》

Another popular type, the quill mum,has long, straight petals like a tube or needle.

VOA: special.2010.06.29

it's like finding a needle in a hay stack.

这简直是大海捞针。

It's like 课堂 - SpeakingMax英语口语达人

Where it stands out from the crowd, or where it can be lost like a needle in the proverbial haystack?

FORBES

So finding a single gene in our DNA is like finding a needle in a haystack.

FORBES: Bringing the Human Genome Into the Doctor's Office

Finding a lost wedding band in Times Square is like finding a needle in haystack only more difficult.

FORBES: Connect