Place this clip right after the reveal of the missing item in your edit, then follow it with the Bruh Meme Sound Button for the reaction shot, or swap that second hit for the Fail Sound Meme Button when the loss is your own fault.
About this sound
A short 3.2-second voice clip of someone flatly announcing 'They stole my Shmunguss' as if reporting a serious crime. The made-up item and the earnest delivery make it sound absurdly grievous, giving listeners that mix of confusion and amusement you get from an overblown complaint about something completely made up.