My brother just came up with the best way to troll your D&D players

storyboard-sketch:

Before they open the final chest at the end of a dungeon, have them roll for Insight. If they score high enough here is what they find out:

“Taking a look at the chest reveals it to be made of some kind of papermache and painted skillfully to look like a real chest. Looking at the back of the map the team has been following reveals it to be signed in sloppy handwriting that says “Enjoy the treasure hunt for sweet rewards!”. The team realizes that….this is a child’s scavenger hunt map.”

Opening the box reveals a horde of chocolate coins. The children must not have been able to finish their treasure hunt once monsters moved in to this location.