After a wake for my friend who died suddenly at age 27, a crowd of us went back to his parents house to eat and drink. I had to take a leak and someone was in the bathroom, so I went to use the bathroom in the master bedroom. As you walk in the bedroom you're facing a full length mirror next to the bathroom entry. Clear as day in that mirror for like 5 seconds I saw my deceased friend standing in the doorway behind me.
Was not drunk at the time.