Place it right after the proud reveal, then follow it with the Bruh sound for a flat reaction to the worthless prize. For a bigger letdown, add Emotional Damage afterwards to stretch the disappointment into a running gag.
About this sound
This 4-second clip catches Captain Jack Sparrow beaming over a jar of soil, repeating his claim to it in a lilting, childlike voice full of misplaced pride. It feels funny and oddly triumphant, because his delight turns a plain handful of earth into a treasure worth boasting about. The line comes from Pirates of the Caribbean: Dead Man's Chest (2006).