I had a dream like that once--and maybe something similar on an earlier occasion. I found it horrible and terrifying. Once I was awake, and realized there was no malevolent being out in the hallway looking in at me, I didn't have any sense that anything external had happened, but boy, was it nasty internally. I don't think I could have had fun with it, though your suggestion that one could have fun with that state actually moderates the recollection for me.