I did once and it was freaky as hell. I was also completely sober at the time and what I saw was weird as hell and pretty messed up looking. Won't go into detail as not to freak anybody out. Didn't really freak me out though and this happened a long time ago. It was all rotten and messed up though.

P.S. Don't get into necromancy, it's dangerous and could get you possessed. I wasn't into it, this just randomly happened on one occasion. I don't normally see dead people. If you were attempting to contact the dead or spirits when this occured or you were involved in occult practices of any kind at the time please specify