I attempt to cast a 3G spell using only Selvala, Explorer Returned in a 4 player Conspiracy game. I have no other available mana sources. Activating Selvala's ability only reveals 3 nonland cards - I can't pay for my spell. What, if anything, are players able to undo here legally within the bounds of the CR?

At first I was inclined to believe that we can rewind every part of this ability, but 717.1 specifically restricts rewinding actions that move cards from a library to any other zone besides the stack - which happened when each player was instructed to draw a card. If you can't unwind that, can you unwind any part of the ability? If not, what happens to my spell that I can't pay for, since I can't undo some of the actions taken while casting it?

I'm aware that we have policy guidelines for rewinding card draws but there's no infraction occurring here; the game just can't resolve itself based on the legal actions taken so far, which feels quite different from rewinding a GRV through a card draw.

Edited Rebecca Lawrence (June 4, 2014 08:42:21 AM)

717.1 is indeed the rule that covers this situation. We don't reverse any actions that move a card from the library to another zone, but we can reverse other mana abilities. In your example, the announcement of the 3G spell and any other mana abilities that you activated are reversed, but we do not reverse Selvala's ability, so the cards drawn will remain in the player's hands (and any green mana that Selvala's did produce will remain in your mana pool).

717.1. If a player realizes that he or she can’t legally take an action after starting to do so, the entire action is reversed and any payments already made are canceled. No abilities trigger and no effects apply as a result of an undone action. If the action was casting a spell, the spell returns to the zone it came from. The player may also reverse any legal mana abilities activated while making the illegal play, unless mana from them or from any triggered mana abilities they triggered was spent on another mana ability that wasn’t reversed. Players may not reverse actions that moved cards to a library, moved cards from a library to any zone other than the stack, or caused a library to be shuffled.

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