soul sand valley: gostlins

New mob for soul sand valley. "Gostlins" spawn in groups and are neutral, with aggression from the player's side jerking in a flock. From them falls the soul for the torch of souls. Upon killing, the block over which Gostlin flies turns into ordinary soil. Also an achievement for his killing "Ghost buster". Simple but atmospheric, and perfectly suited for this biome. I took the idea from a video on YouTube. There were few views, and I doubt that it was offered before.