Bad jokes need good sound design too. A duck quack sound effect exists for exactly that purpose — a silly, deliberately deflating punctuation mark dropped in right after a groan-worthy pun or a joke that's supposed to land badly on purpose.
Why this sound fits bad jokes so well
The duck quack carries an inherently silly, lighthearted quality that signals to the audience the awkwardness was intentional. 
A kittycore 9 silly cat jumpscare meme — view on SoundGIFs Rather than letting a bad joke sit in genuine awkward silence, this sound confirms the joke was meant to fail, turning the failure itself into the actual punchline.
Signaling intentional cringe
There's an important difference between a joke that genuinely falls flat and one that's deliberately written to be groan-worthy. This sound effect helps mark the second category clearly, letting viewers know the awkwardness is part of the bit rather than an actual mistake.
Where it works best in an edit
This sound effect shines right after a deliberately bad pun, an obvious setup with a weak punchline, or any joke built specifically to make the audience groan rather than laugh outright. Dropping it in immediately after the joke lands reinforces that the reaction is expected and intentional.
No literal duck required
Despite the name, this sound gets used constantly with no actual duck anywhere in the video. Its silly, comedic quality does the work on its own, similar to how a slide whistle sound effect for comedic fail edits gets used purely for tone rather than literal accuracy to whatever's happening on screen.
Comparing it to harsher fail sounds
A duck quack is noticeably gentler than a harsher fail or error sound effect, making it better suited to lighthearted, groan-worthy humor than to a genuinely embarrassing mistake. Using a harsher sound for a deliberately silly joke would clash with the intended tone, undercutting rather than reinforcing the humor.
Keeping the joke's tone consistent
Matching sound intensity to joke intensity matters here — a small, silly pun deserves a small, silly sound, while a bigger comedic swing might call for something with more weight behind it.
Avoiding overuse
Like most comedic sound effects, using this one too often across a single video wears out its charm quickly. Saving it specifically for jokes built to intentionally fail keeps it landing as a genuine punchline rather than background noise.
Conclusion
A duck quack sound effect turns an intentionally bad joke into its own kind of punchline, signaling to the audience that the groan was the whole point. Browse SoundGIFs' comedic sound effects library for more sounds built to punctuate a joke that's supposed to land badly.