Got to legally stack my opponents deck yesterday

Yesterday I was playing some EDH at the kitchen table with my usual group when a very unlikely thing happened.

I was playing a Kozilek, the great distortion deck, to my left was nekusar and to my right was narset. We were in maybe 10 turns, I had a big pile of rocks and had cast a couple big bombs, nekusar had a couple howling mine effects and it's commander and Narset had a staff of progenitus, narset herself and something like 10 mana available at its next untap.

Narest player passes to me after tapping out for his commander. I draw my card and realize there is nothing in my hand that can stop him from stacking his deck and most likely winning the game. The nekusar player kindly reminds me to "draw three take three" and I happily oblige. Lo and behold 2 cards down is good ol mind slaver and I have exactly 10 mana. So I drop it, sac it naming narset and pass turn.

Nekusar goes and then it gets to narset and the pilot shows me his hand containing time stretch and vandalblast. He and I briefly die of laughter. I do a couple things with his hand that I could have done better but leave myself enough mana to scroll rack away vandalblast and time stretch before using staff of progenitus on narset, let her go to the command zone, go through his whole deck that has no creatures and reorganize the whole thing. I took out every piece of junk card I could find and interspersed them with basic lands and stacked the top 30ish cards of his library and passed turn to myself.

I have played magic for something like 12 years. I have never seen anything like that happen and I don't expect to ever get to hold my opponents whole deck and literally organize it however I want ever again.

TL;DR I mindslavered a creatureless narset edh deck With staff of progenitus and got to completely reorganize his whole deck.