How to Reveal Blocks Only After a Player Beats a Boss

Linking a Revelation to an Advancement

Revelations are controlled entirely by advancements, so the boss fight must award an advancement. Vanilla already grants advancements for defeating major bosses, and you can reference those directly in your revelation file. If you want a custom trigger, write your own advancement with criteria that fire on the boss's death, then point the revelation at that advancement's ID.

Per-Player Visibility Explained

Visibility is tracked per player. Two players on the same server can see different versions of the same block depending on whether each has earned the gating advancement. This means you do not need to change the world when the boss dies; the mod handles the swap client-side per player. A player who joins later and has not beaten the boss still sees the disguised version.

Practical Tips

Test with two accounts or two players to confirm the split visibility works. Remember that the disguised block is what players mine and interact with until revealed, so choose a placeholder that makes sense thematically. If you want the reveal to feel dramatic, pick a fake block that looks plain, then map it to something lush or valuable once the advancement is granted.