X Marks the Spot is an object in the Shipwrecked DLC that appears only after its location has been revealed by reading a Message in a Bottle. It appears as two X-crossed bones over disturbed soil. It can be dug up with a Shovel or shot with a Boat Cannon to reveal Bone Shards and a Chest containing several pieces of treasure. There is a 1% chance for a Booty Bag to spawn as well.
Possible Treasure
There are fixed presets of the treasure chest loot, mixed with some random loot plus some chance loot.
Random Loot:
One of these items is always added to the treasure chest, based on a weight list (the higher the number, the higher the chance of appearance).
Chance Loot:
Each item in this loot table has its own chance of appearing, or not. So it is possible to get every item or none.
Standard Random Loot:
Most Random Loot outcomes have the same Loot Table, all equally weighted (1):
Standard Chance Loot:
Most Chance Loot outcomes have the same Loot Table: (25%)(25%)(10%)