Place this clip at the reaction beat right after the reveal, then follow it with the Tuturu button for a lighter anime tag, or precede it with a Windows XP Error cue when the surprise comes from something going wrong.
About this sound
This clip is Mari Ohara delivering an extended, high-pitched 'Oh my god!!' in English, stretching the exclamation for about ten seconds. It feels gleefully shocked and over-the-top, turning a small surprise into a dramatic reaction that listeners instantly read as playful disbelief rather than real panic or alarm.