Selvala, Explorer Returned has the following ruling:
If you activate Selvala's ability while casting a spell, and you discover you can't produce enough mana to pay that spell's costs, the spell is reversed. The spell returns to whatever zone you were casting it from. You may reverse other mana abilities you activated while casting the spell, but Selvala's ability can't be reversed. Whatever mana that ability produced will be in your mana pool and each player will have drawn a card.
I have 2 questions about this ruling.
Does this mean that, in conjunction with rule 121.8,
121.8 If a spell or ability causes a card to be drawn while another spell is being cast, the drawn card is kept face down until that spell becomes cast (see rule 601.2i). While face down, it’s considered to have no characteristics. The same is true with relation to another ability being activated. If an effect allows or instructs a player to reveal the card as it’s being drawn, it’s revealed after the spell becomes cast or the ability becomes activated.
if you are unable to cast the spell, and it returns to your hand, the cards drawn off the parley ability are kept face down... permanently? In my interpretation, even if you were to recast the spell, since it changed zones, it would have no knowledge of it's previous self, and therefore would not allow the cards to be seen. Is this correct?
Why does this happen? What rulings indicate that the spell should be "un-cast," and is this a unique case? Or is there a precedent with another ruling that does the same?