I had a very realistic visual hallucination once (hypnopompic).
I was coming out of a nap while I had a fever.
I looked over, and beside the bed was a young woman staring at me intently.
She leaned over to bite/eat me, but calmly and without any emotion.
As soon as she got within touching distance of me, she started to vanish, from the centre-out, and within a couple seconds was totally gone.
I was really struck by how real she seemed.
She looked exactly like a real person.
But I just knew she wasn't real (the same way that you just know things in dreams).
Because of that, I didn't find it scary at all.
I remember being a little curious what kind of sensations I would "feel" when she actually made contact with me, and was a mixture of disappointed/relieved when she vanished at that point.
But strangely(?) not scared.
I had something similar, also when I had a fever. A little boy with clothes as if he was from the 20s was standing near my bed and looking at me. Really strange. I was not scared either.