Examples:

• For my next trick, a needle in a haystack.
• Are you familiar with the term "needle in a haystack"?
• This is like a needle in a haystack, isn't it?
• Makes it a bit of a needle in a haystack.
• In other words, we're looking for a needle in a haystack.
• It is like looking for a needle in a haystack.
• Everyone talks about a needle in a haystack.
• I need you to find a needle in a haystack.
• This is one needle in a haystack we better find.
• Be like looking for a needle in a haystack.