Ok... if the lack of food and drink isn't killing you by now, I'm sure the suspense is... so I shall now reveal that this story is in fact....
TRUE !!!
That is, the events that I described in this story actually took place.
I should add at this point that what our guest was attempting is extremely dangerous and several people have in fact died trying to do the same thing so I would urge anyone reading this NOT TO TRY THIS AT HOME - at least without serious consideration of possible consequences and a thorough investigation of your own.
I believe that my guest was absolutely genuine and was only interested in practicing deep meditation and exploring the nature of reality - that he had no interest in pulling an elaborate deception. It is possible that he may have survived the process by a combination of wishful thinking, willpower and self hypnosis - or some other rational explanation.
As with anything, you are free to believe what you like - what makes the most sense to you. Like I say, this story really happened, pretty much exactly as I described. What it means is another story altogether.
I do think you told me a bit of this before...