Different Wither Types

What if you could replace the core of the wither with a different block to elicit a different fight and reward.

The different nether star would add a new effect to the beacon/new recipes

The way you would tell the difference is the eyes would be the colour of the blocks and so would the shield in phase 2.

I will include 2 examples of how this could go down.

1. Copper block.

The skulls would fly faster but do less damage

When phase 2 starts it shoots a lightning bolt to you and any arrow shot at the wither would send another weaker lightning bolt every time it is shot.

The reward would be a (insert electrical word) star and when chosen in the beacon whenever you get under half health it shoots a lightning bolt to the target with depending on the power of the beacon the cooldown.

2. magma block

slow firing skulls that when hit you or in a radius around you set you on soul fire

when you reach phase 2 like the ender dragon it will occasionally shoot pools of fire

The reward would be The Blazing star. While it does not add anything to the beacon when used in a potion would be a better fire resistance that it heals you slowly when on fire (not in lava) Is this balanced probably not but I would want your feedback