The Watcher

You are an ordinary living being. Living ur normal life, recently, you started noticing a black shadow out of the corner of your eye with an accompanying chill. However, when you turned around to see who this person was watching you, there was no one there, as if it were just a cruel joke of your brain because of another lack of sleep.
But it's not for nothing that you've been feeling a gaze on yourself for 3 weeks, which makes your blood run cold, and a cold drop of sweat runs down your temple. You feel like you're going crazy. Until one day this unknown mysterious creature appears in your field of vision. But...This creature does not interact with you in any way, no matter how hard you try and want to. An attempt to approach is unsuccessful - the creature immediately disappears into its cool mist enveloping it.
You were at home right now, minding your own business. And this creepy person appears again, 5 meters away from you. He stands there silent, staring unblinkingly. Again.