So, my friend told me he had a nightmare in which a creepy old lady was trying to kill him and he couldn't move. He then woke up but couldn't move (SP I guess), and felt like the old lady was behind him, slowly moving towards him, to the point where he felt a numbing cold go through his back (he thought it was the old lady leaning on top of him or something like that) and at this point he really freaked out and could finally move. (he also mentioned that while he was "awake", he had some weird visions in which the old creepy lady was staring at him, can these be HI?)

This morning I tried DEILD and started feeling SP, my mind started wandering around, and I kinda controlled my hallucinations, I don't know why but I thought of myself going to the bathroom and brushing my teeth (I could taste the toothpaste, but I was still in bed) Then all went black, and I was there on my bed not being able to move, then I knew SP had kicked in. I suddenly felt a numbing cold running through my back (just like my friend had described it) and heard the sound of the shadow hands from zelda made (ocarina of time, forest temple, remember? the creepy ones that formed a shadow under you and pulled you out of the temple). At this point I started to freak out but decided to stay calm and imagine myself somewhere else, I did and that's when my lucid dream started

Err... my question is:
Is it normal to feel that sudden cold running through your back when getting SP? and also, My friend had HI's of a creepy old lady, mine were about the creepy Zelda hands... are these possibly related to a childhood fear?