Place it right after the reveal in a reaction edit, following a build with Sudden Suspense and letting Oh My God Wow follow as the next reaction, while Huh from Ceeday works best before it as a smaller setup question.
Über diesen Sound
This just-under-ten-second clip catches Joel mid-reaction, blurting out a sharp, drawn-out 'Nani' as a sudden shock lands, his voice jumping from confusion to wide-eyed disbelief in a single beat. It feels startled, silly and instantly quotable, the kind of over-the-top anime-style gasp that turns an unexpected twist into a joke before anyone has time to explain it.