This is what I'm planning:
The player starts with Slenderman having a 10-second cooldown and a 1/10 chance of Slenderman teleporting right in front of him. When he collects a supply the cooldown reduces to 9 seconds and the chance is now bigger as 1/9. Whenever he collects a supply, the cooldown is lowered by 1 second and the chance gets higher by reducing the denominator by 1. The mission has 8 supplies which will randomly spawn in 15 or maybe 20 different spots. Didn't get it? For example, when the player already collected 7 supplies, the cooldown is now 3 seconds and the chance of Slenderman teleporting is 1/3. If I can, I will mark spots where Slenderman can spawn, then Slenderman will spawn on the nearest spot to the player.
--EDIT--
I have a problem, I was planning to make him teleport away if out of sight, I can do that, but I don't know where. Can somebody give me an idea?
--EDIT--
I have a problem, I was planning to make him teleport away if out of sight, I can do that, but I don't know where. Can somebody give me an idea?