New End Biome: Shrouded islands

These would be random islands invisible beyond a certain range to players, appearing to be completely empty spaces between visible islands.

But once inside the 'event horizon' (being close enough to the geographical center of the biome), the player can see whatever is on the island.

And perhaps there is a new shroud-stone block that generates this event horizon. So if a player wants to mine that block and take it somewhere else in The End, they could use it to hide their End base. Or maybe take it back to the Overworld, where they could use it to hide a sky build.

Or use the shroud-stone block to hide the components of a trap, or your favorite farm, or whatever.

Trying to find a shrouded island without commands would be a mix of luck, intuition, and sheer bravery. One way might be to fly between islands that seem unnaturally far apart (and hope you don't crash and die). More dangerously, you might try and throw an ender pearl and see if it gets stopped by something you can't see.