Your Friend follows you around, but is only visible to you at night. He doesn't talk much but he studies you. He likes to protect you, so he can study you more

He is tall, dark, and skinny. His skin resembles a tree bark. His mouth is huge and can swallow things as large as humans

You are going to sleep when you notice your shadow seemingly moves around. You get up to notice that an eldritch abomination is watching you simulating what you assume is a smile.