Number XI: Unmei

Immortal
At the beginning of each player's upkeep, that
player looks at the top two cards of their library.
They place one card face-up and one card face-
down. You choose one pile and exile the card
face-down, you may look at and cast that card
for as long as it remains exiled, and you may
spend mana as though it were mana of any type
to cast that spell.