Place it right after the moment that goes wrong, then follow it with Anime Wow for a beat before the next scene. If the confusion needs a heavier payoff, use Dun Dun Dun instead as the closing sting.
Über diesen Sound
This is a very short spoken line in which a voice declares 'I am confusion' in a flat, bewildered tone, lasting just over a second. It lands as a blunt, funny admission of being completely lost, perfect for moments when an explanation makes things worse instead of clearer. The version here is the WKC edit from 2020.