Need horror mod ideas!

Make spirits appear with smoky particles around a zombie in a haunted house. Remember that the zombie needs special white armor that gives off particles and does not have armor points

 Most people are scared of the unknow and darkness. I also find sounds scary sometimes like the cave sounds.
My idea is that by adding something like... You know it is there but you don't know what it is and if it is deadly and stuff.
I imagine walking through a forrest at night and knowing that there is something scary that could be waiting behind every tree and hill (You could add Herobrine, but that would feel more like a joke that a horror feature tho.) Just imagine hearing twigs crack behind you or you hear something getting through a bush in the dark. Sounds, darkness and the unknown. That is my idea.

 Or imagine going caving with few friends and suddently one of them dies in a nearby cavern and in the chat there is something misterious like"Player_1 was killed by It" or "by Him" or "Player_1 was choozen by it" You know there is something hunting you down but you don't know what. Also imagine your friends wanishing one by one until only you are lef or something.