damp squib

US /dæmp skwɪb/
UK /dæmp skwɪb/
"damp squib" picture
1.

something that is expected to be exciting, impressive, or effective but turns out to be disappointing or a failure

:
•
The highly anticipated concert turned out to be a bit of a damp squib, with poor sound quality and a short setlist.
•
Despite all the hype, the new product launch was a bit of a damp squib, failing to generate much excitement.
:
damp