The Winter King

Whenever a creature you control deals combat
damage to a player, look at the top three cards of
that player's library, exile one of them facedown,
then put the rest on the bottom of that library in
a random order. You may play that card for as
long as it remains exiled, and mana of any
type can be spent to cast it.
"You can ask me anything. You could have always
asked me anything, Arthur."
—The Winter King