This feature is exclusive to Java Edition and Legacy Console Edition.
Curse of Vanishing is an enchantment that causes the item to disappear on death.
Obtaining
Curse of Vanishing can be obtained only from chest loot, fishing, or trading for enchanted books.
Usage
When the player dies, the item disappears instead of dropping on the ground. The item may still be dropped normally.
The effect can be prevented by setting the keepInventory gamerule to true.