Soul sand valley particle effects

Right now the origin of soul soil and sand alike remains a mystery, though my idea is a particle effect, it does explain the soul soil and sand and probably even the soil fire and even the blue fog in the soul sand valley.

  The idea is that a "soul" (i imagine it will look like some sort of a blue ball with blue trails) will fall into the ground from the sky, literal souls that goes to hell. They would look like animals or people that have died in-game or not just to give of a spooky feel, but i imagine it will be more on villagers. I imagine it will only be an easter egg that any mob that died within a time period (could be random) will be seen in your nearest soul sand valley.

  Another particle effect exclusive in soul sand valley is that when an undead is killed within that biome a "soul" will appear and fly back to the ground.