The prophecy system was removed from the game in version 3.17.0. Itemised prophecies no longer exist in Path of Exile.
Monstrous TreasureIn a long lost dream, great foes hide in tiny boxes, but so do great rewards.You will travel to a map where the monsters lie in wait, open the boxes they guard, and slay them all.Right-click to add this prophecy to your character.
Acquisition Not in game Seal cost: 2× Silver CoinMetadata Item class: Currency Item
Go to a map area. The area contain 36 strongboxes where all non fixed-placed monsters are packed into. Note: This prophecy stacks with Zana's ambush mod.
All non fixed-placed monsters are packed into a strongbox.
Able to stack with other sources of strongboxes (Ex. Zana's ambush mod, Ambush Scarabs, Bountiful TrapsBountiful TrapsIn a distant dream, six traps with the promise of treasure wait to be sprung.You will enter a map that holds six additional Strongboxes.Right-click to add this prophecy to your character.).
Removed the Prophecy mechanic from the game, and moved many of its rewards to other content.
Silver Coins can no longer drop. Existing Silver Coins and itemised Prophecies will be deleted from your inventory and stash the next time you log in after the launch of 3.17.0.
Monstrous Treasure is now a special map crafting option, and can be accessed via the Shaping the Skies notable on the Atlas Passive Tree, or as one of Kirac's master mission options. [Undocumented This change was not documented by any official sources. It was discovered through player testing or datamining.]