Place it at the end of a setup line as the unexpected answer, then follow it immediately with a shocked sound for the reaction shot and an oh no no no laugh to close the sequence while the caption stays on screen.
Über diesen Sound
This clip is a voice-changed voice saying the single nonsense word Schmurgendurhenburgendurgen in under a second. It feels deliberately absurd and funny, like a made-up reply that derails a serious moment. It comes from a TikTok meme built around pronouncing the long gibberish word.