This gets a lot more interesting if each player names a card in their upkeep.

I'm unsure if you meant "last chosen name". Keeping track of all the names mentioned sounds rough. And having to come up with every possible permutation of a red direct damage spell or enchantment removal spell in rounds 7 to 23 is really annoying (since they're the only things that will kill you at that point, but clearly you built a deck to turtle. So a 40 round game of 'draw-go' doesn't seem all too unrealistic.)

But that casting cost and mythic status seem to infer that's what you were going for. Hm.

Yeah you'd have to track each card you name with it but it's essentially the same as getting a copy of gideon's intervention or pithing needle each turn. Maybe you remember all the cards you've named or maybe you do like me and have little pieces of paper you stick on it.

Yes, it's up to the owner to remember all the threats the opponent could have OR for them to have a way to search their opponent's library so they know what cards to name

Big ouchie. I do like the sound of an easier to cast one which each player gets to contribute a card to, as well.

I don't know if I like the design of a communal one. It's kind of funny how quickly both decks would run out of gas. As more cards get named, less happens on each turn and thus the turns go faster and then more things get named.

It seems like a recipe for long games but eventually the writing would be on the wall: Either no player can do anything and you might as well count who's going to deck out first, or one player has something that isn't affected (like a non activated token maker or passive life drain) and both players acknowledge that that's going to make the difference.

I play a deck in pioneer right now and very often I'll have used an extraction effect and I'm just ticking off cards from their deck. It's surprisingly easy to remove all the threats from someone's deck. Knowing that this is in play would make it easier because even if they draw their one-of creature, you disable it the very next turn.

Honestly, I think I should change it to be both players but not reduce the cost.

Also, edh games would be wild. Commanders become disabled instantly but you're never going to be able to name all the removal. The politics involved in who names what? Oooh

How about there only being a single slot of ban, but each player gets to change the ban (probably at the end of their turn so they can't just unban their card). Though that does still lead to commanders being gone forever. For which I'm tempted to say "Well, GOOD" but that does rather neuter the format a bit :)

It'd need to be a ton cheaper if that was the case. That would make it like nevermore with phasing... Maybe an idea for another card but that's two seperate designs