The phrase 'I didn't see you there' is one of comedy's oldest fake-surprise gags, appearing for decades in cartoons, sitcoms and sketch shows whenever a character pretends not to have noticed someone standing nearby. Online it became a staple reaction sound for short-form video, where creators use it to play off jump-scare fake-outs, surprise guest appearances and 'caught red-handed' moments. Its charm is the obvious lie: everyone knows the speaker saw exactly what was happening, and that shared wink is what keeps the line funny years after its first use.