Place this clip right after the reveal in a reaction edit, preceded by a sudden suspense sting and followed by a damn meme button to close the sequence, or by Nelson's Ha-Ha! when the mistake turns into group teasing.
Über diesen Sound
This is a drawn-out vocal reaction stretching the words 'o-ohhh' over about four seconds, delivered as a slow, rising realisation. It gives a listener that sinking, half-amused feeling when a mistake becomes obvious, a plan falls apart, or an awkward truth lands a second too late for anyone to fix it.