The Presence

Basic Information
The Presence is a shapeshifting monster, taking the form of anything, from a puppy to an eldritch horror. It appears in your dreams or as a hallucination, and eventually will hunt you down after becoming corporeal.

How to Prevent being "Haunted"
Preventing being haunted is impossible, although you can reduce your chances of being hunted if you stay in brightly lit areas or stay near specific runes.

Haunting Behavior
The Presence will haunt you by appearing in the corner of your vision, seemingly taunting you.

In later stages of haunting, the Presence will appear in the front of your vision, even rushing at you as if to attack.

Becoming Corporeal and The Hunt
Eventually, the Presence will become corporeal, and will stop haunting you... but it'll start Hunting you.

The Presence will play with you, ambushing you to terrify you, then disappear into the shadows. But then, the Presence will get bored with playing with you,

And go in for the finisher.

Surviving being Hunted
If the Presence starts Hunting you, you can hold it off by using bright lights and specific runes, however eventually the Presence will ignore these, so using these methods only prolongs your life slightly.

If you manage to somehow get a good hit in on the Presence, it will flee.

If you somehow kill the Presence, it will reanimate a bit later. If you destroy the corpse, It will actually RESET to simply Haunting you again. This is the only real method to stop The Hunt.

(going to add more in a bit)