Spectral

Spectral is a mod that currently adds 4 items, three of which are pictured below:

The first, Spectral Dust, is crafted from phantom membranes and can either be eaten to turn temporarily spectral, or put onto a mob to turn it spectral.

The second, Spectral Goggles, put who wears them to enter a spectral state, allowing them to see and interact with spectral blocks and entities. These goggles can be crafted with Spectral Blocks, Spectral Dust, String, and Iron ingots.

The third, Spectral Block can be placed down as a normal block, but can only be seen, collided with, and broken by spectral players and mobs. (This function is per-player, so you might be able to see spectral blocks while your friends cannot!) This block can be crafted from Spectral Dust and glass!

The fourth and newest, Block of Cold Iron is the same as a spectral block but can only be interacted with by non-spectral entities!

Mechanics

The basic mechanics of Spectral function as such:
There are two states living entities can be in, either normal (non-spectral) or spectral. This depends on their spectral_vision attribute (0 for normal, 1 for spectral). A non-spectral entity cannot see, hit, or push spectral entities, and it cannot break, collide, or see spectral blocks. Spectral entities cannot see, hit, or push non-spectral entities, but can fully interact with other spectral entities and spectral blocks.

Known Issues:

-Spectral blocks do not properly change render states when sodium or other optimization mods that affect chunk rebuilds are installed
-Shadows appear ontop of Spectral blocks even when the player is not spectral
-If you encounter any other issues or have any suggestions, please post them on github issues for me to see!