I'll say. I haven't had your experience in particular, but the first thing that came to my mind was sleep paralysis - which is mentioned in bfv's link above. From the bit I'm looking at, they seem to be one and the same, if not similar.
Never want to experience that again. Scared the living balls outta me thinking I was going to die. My experience was seeing lightning and (felt like) I was experiencing lockjaw from/while being electrocuted everytime I tried to breathe. Again, not anything I ever hope to experience again.
EDIT: While I can't seem to find where my experience would fit in to the Jungian mold, shadow definitely is on the list and an interesting read.