Corrupted Tutelage

Split second
Look at the top {x} cards of target opponent's
library. You may choose up to two target cards
and put them into exile.Then that player shuffles.
If {x} is 5 or more, that player also reveals that
many cards they own from outside the game.
Choose one, then exile it. For as long as any
card exiled with Corrupted Tutelage remains
exiled, you may spend mana as though it were
mana of any type to cast that spell.