foggy mob

I found idea on this site and decided to supplement it. The idea was to add fog in the swamp biome to Minecraft. And so. I would like the fog to be not constantly, but intermittently. It could be of different stages, for example, at the first stage, the fog would simply spread over the ground, and with each subsequent stage it would rise higher and become thicker. During fog, the player's visibility would decrease. With each stage of the fog, all the sounds around would become quieter, and the animals would try to hide or escape from the fog zone, which would spread not to the whole swamp, but only to parts of it. But the fog is not just a natural phenomenon, but something dangerous, at the last stage of the fog, a new scary mob may come to the player. He would appear on the border of the player's visible zone and gradually, silently approach him. He should be scary enough that players are afraid of the fog, he should be 2 blocks tall, or slightly taller. Its texture should be white or light gray with empty black eyes. He should be thin, and there should be ribs on his stomach that shine through his thin skin. He must be strong enough. To avoid meeting him, you need to have time to get out of the fog zone before its last stage. If he started chasing you, then he will not back down, and at some point he will attack you with a sharp and frightening sound. I think such an update will be interesting, because there are not so many mobs left in minecraft that really scare players.