For any magic trick or other illusion, just figure out how you would do it. Chances are that’s how the mysterious achiever did it too.
The coral castle is vaguely familiar to me, but I have often wondered how puzzling it might be to someone else if I chose to move something heavy around by simply putting a pad of ice under it. Just move it into place and then leave it alone.
How do you 'simply' put a pad of ice under a 30 ton rock ?