If all of the damage is prevented, Mjlnir's effect no longer applies
As you embark on creating your own MTG proxies, remember to respect the games legal boundaries and the communitys ethical standards
So, if you want to have a bit of comedy in your act, take someone's powers away, or have an ongoing bit in your act, PRISON DECK is for you
At instant speed you can pay to make X 1/1 Citizen dorks and your stuff gets indestructible for the turn, which is a nice variant on your answers to mass removal, and this is a strong combat trick where you can cast this after an attack your way, make a bunch of 1/1s, block, and keep them alive, or you can just use this in response to a big sweeper like a foe's Wrath of God when you only have two for the X to save your team and get in a Commander bump
As a fine card on its own and one that's incredibly strong with other Humans on the battlefield, this is a great example of what you're looking to play in these kinds of decks