Overworld zombie giant boss

The zombie giant has been one of the first boss-like mobs.I think adding it to vanilla Minecraft as an overworld boss is a good idea. It would be a rare abundant  structure that's half buried in a hill or similar.

It will have 3 levels, the top one will have a lot of rooms with zombie spawners and really basic loot. The middle one will be a maze like boss fighting arena with large tall corridors where the boss will wander in, spawning waves of normal zombies and husks to attack you much like the potato boss from the April fools snapshot.And the bottom layer would contain all the loot (or the loot is just scattered across the maze in chests).

There could also be a new chiseled block in there.