Horror entity

HELP ME A HORROR ENTITY

I need help making my entity work like this:

• It watches you from far away.
• If you look directly at it, it instantly despawns.
• Every 4 minutes or more, it turns invisible and moves closer.
• When it gets about 4 blocks away, it teleports behind you and starts chasing and play a loud sound.
• While chasing, it can randomly despawn at any time. it should get harder to run away from and more aggrassive the more the days go.

Basically, I want it to feel creepy, kind of like the entity from Pixel's video: "I Created My Own Terrifying Minecraft Mod" [https://www.youtube.com/watch?v=Hg80jnO93RM&t].