"SlenderMan" is a hostile mob just like "Herobrine". He travels in the night and is very powerful. If you get close to him your screen will get blurry. The only way to attack him is with a diamond sword or a slender sword. There is also slender armor. Slender armor protects you from "SlenderMan". Your screen will not get blurry if you wear a slender helmet. You get the materials to make slender thing by killing "SlenderMan". When you kill him he will drop something that's called a "Child's Soul".