End update biome

I think that an End update should contain something similar to the overworld's Deep Dark biome. But instead of focusing on sound and staying quiet it could focus and visibility and staying unseen.

A new block could detect a player within a set range, and if there is a direct line of sight from the block to the player it would activate and start a countdown so long the player is visible, and to avoid the countdown reaching zero you would have to take cover.

If the countdown reaches zero something like a powerfull Warden styled mob could spawn, that begins hunting the player after detecting the player.

I believe a biome/structure like this would be perfect for an end update, with it adding fear and caution to exploring the new end dimension without clashing with the vanilla feel.