3am riding solo at Mountain Mayhem some years ago, in the mist I saw what I thought was an undertaker wearing a stove pipe hat walking towards me, I stopped and walked back to the marshall point I’d just passed quite shaken, turned out to be a fence post and I was hallucinating through tiredness :-0
And then there was the guy singing Elvis songs in the woods at Mountain Mayhem a good few years ago, I thought it was a supporter, turned out to be a local nutter who was carrying a knife !