Download Minecraft Man From the Fog Mod:-

It adds a horror entity which sees you and Spies your Actions. This mod aims to make minecraft scary and to make it a horror game. and through the entity it gives game a scarier theme the entity name is man from the fog. the entity spawns every night. When it spawns it looks you from distance and if you ignore it it comes closer. Or if you look at it the entity goes violent and attacks you.

Download mod for forge 1.20.1:-