Alright, I was reading an idea someone had in the Writer's Block section about a chest that made your fears come out of it (the idea was scrapped quickly I believe), but it wound up giving me a thought. I was thinking either an old "treasure map" that would cause people who look at it to compulsively seek the treasure it lead to, imagining clues in their environments that led them closer to finding the treasure, only to eventually dig up a chest and have some anomalous effect I haven't decided on yet to occur.
The other possible thought I had was as a Wondertainment item. A pretend pirate set consisting of a treasure map, flintlock pistol, sword, and pirate hat. The map would always lead to a treasure, but in the path to finding it all manner of cliche pirate-y stuff would occur, like being attacked by rival pirates, Giant Squid attack, etc. After finding the chest and opening, I imagine it being full of chocolate dubloons. Because that would totally be worth being attacked by pirates, squids, and other things.
Anyway, any feedback on the idea, thoughts to improve it, etc., would be greatly appreciated.