Put it just before the reveal in a short edit, then follow it with Anime Wow for the surprised reaction and Dun Dun Dun for the dramatic twist, keeping it as the quick beat between them.
關於此聲音
This is a very short voice clip, under a second long, of Kikirara Vivi saying 'Ya~rashii' in a drawn-out, playful voice. It feels cheeky and a little suspicious, like a cute accusation delivered with a smile, and it works as a quick reaction to something that looks slightly off. The clip comes from Kikirara Vivi.