Shallow Ones Blessing

At the beginning of the game, if Shallow Ones Blessing is in your hand, discard every card
named Shallow Ones Blessing from your hand.
If you discard it this way, you start the game.
Whenever you were to mulligan, if you have
Shallow Ones Blessing in your hand, discard it.
{t}, Sacrifice Shallow Ones Blessing: Add one
mana of any color for every Purgatory in your graveyard.