So basically, I know there is already a mod for this. But I want to suggest a "Enhanced" version of it.
New Mob: Slenderman Spawn: VERY VERY RARELY in forest-type biomes, and also very rarely in the end.
Behaivior: When looked at, he will drain your health quickly. It will also shake your screen and cause the static noise from the real game (Not eight pages, but the one from arrival). If you run away, he has a chance of springing out tentacles from his back and using it to bring you towards him, then turn you around and make you force-stare at him. You can make his tentacles go back in and release you if you hit him. He can teleport like a enderman. He usually uses his teleport when hes behind you, and usually won't teleport right before your eyes. He doesn't really do damage with melee, but if hes close enough behind you he will kill you. Health: 100
Drops: 1 Slender Head, 1-3 Slender Pages, 2-3 Ender Pearls.
New Armor Piece: Slender Head The Slender Head is a wearable item. It CAN be placed on the ground as a trophy too. When you wear it, any mob you look at can be drained health until they are 50% down (To keep it from being OP), and also causes screenshake and static noise. Opponents/Mobs that aren't looking at you will not be affected.
Static (1-3): Lets you drain more health by staring, 10% more health draining per level
New Decoration: Slender Pages Placing one of these will place a random page from the game. No other uses
New Mob: Proxy A zombie with 2.0 more damage, slows you down on hit and is slowed down in light. Has 30 health. Spawns at the same rate as endermen in the overworld. Drops: Mask
New Item: Mask Nothing cool, just a little proxy mask to wear.
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