I don't fully understand how the Dusk//Dawn and Snapcaster Mage interaction you mentioned works. How could it "grant" a flashback cost of 5WWWW, but you not have to pay that to flash it back? I understand not having to pay that for Dawn, due to aftermath, but how can you get away with flashing back Dusk by paying anything other than the flashback cost it was granted? Can you point me to where in the comprehensive rules that is supported? Thank, judge!
Right, so Snapcaster Mage grants Dawn /// Dusk flashback with a flashback cost equal to its mana cost. When it’s in the graveyard, its mana cost is 5WWWW, so that’s what its flashback cost is there.
However, the value of this flashback cost is constantly re-evaluated as per CR 702.1b: “An effect that grants an object a keyword ability may define a variable in that ability, such as X or its “[keyword ability] cost,” based on characteristics of that object or other information about the game state. For these abilities, the value of that variable is constantly reevaluated.”
When we go to cast the card from the graveyard, we choose which half we’re casting as we put it on the stack. When we choose to put Dusk on the stack, the flashback cost granted by Snapcaster Mage is now only 2WW because that’s Dusk’s mana cost on the stack, since the characteristics of Dawn are treated as though they don’t exist as per CR 708.3b. So when you choose to pay the flashback cost, that’s the alternate cost that’s locked in at that time.
