I had an interesting situation come up during an EDH game.
Player 'P' player relentless rats
Player 'N' playing almost nothing relevant
Player P gets Thrumming Stone and relentless rats going. P has no cards in hand and thrums through his entire deck casting each rat he reveals (All of his rats). He also has no rats in his graveyard or exile.
What is the rule that prevents P from losing because of an illegal deck (since no rat allows more than 1 copy to be played). Is the situation any different if this happens in Legacy rather than EDH/Commander?
The text stating you may play any number of Relentless Rats is considered a characteristic of the card rather than an ability that could be removed.
EDIT: While it technically can be removed, since was already applied before the game begins, it's similar to removing all abilities from a creature with a CDA that changes its own color. That ability will be applied in Layer 5 before its abilities are removed in Layer 6. So in this case, the ability is applied in what is basically Layer 0 before it can be removed in Layer 6. That's what I meant when I said it was a characteristic of the card. So yes, technically, if you cast Sudden Spoiling vs. Relentless Rats, the rats will be able to get a boost from Muraganda Petroglyphs but the deck will not become illegal.
There is no state-based action that causes a player to lose the game if they have an illegal deck. That game loss can only be given from outside the game. Only a tournament / game official can do that; as such, for a casual format, check with your playgroup, but for a tournament format, deck legality is determined upon presentation and doesn't change during play (for example, Research can cause a game 1 deck to change from its maindeck listing).
Maybe this reality is actually an alternate reality of a reality in which New Phyrexia was the joke expansion and Mirrodin Pure was the obvious expansion, except our reality is the Time Shifted reality which is opposite of that other reality which is that actual reality.
Player 'P' player relentless rats
Player 'N' playing almost nothing relevant
Player P gets Thrumming Stone and relentless rats going. P has no cards in hand and thrums through his entire deck casting each rat he reveals (All of his rats). He also has no rats in his graveyard or exile.
After P stops thrumming N casts sudden spoiling.
What is the rule that prevents P from losing because of an illegal deck (since no rat allows more than 1 copy to be played). Is the situation any different if this happens in Legacy rather than EDH/Commander?
EDIT: While it technically can be removed, since was already applied before the game begins, it's similar to removing all abilities from a creature with a CDA that changes its own color. That ability will be applied in Layer 5 before its abilities are removed in Layer 6. So in this case, the ability is applied in what is basically Layer 0 before it can be removed in Layer 6. That's what I meant when I said it was a characteristic of the card. So yes, technically, if you cast Sudden Spoiling vs. Relentless Rats, the rats will be able to get a boost from Muraganda Petroglyphs but the deck will not become illegal.
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