Markash, the Crimson-Braided

Double strike, menace
Whenever Markash deals combat damage
to a player, that player may sacrifice a creature.
If they don't, create two treasure tokens and
exile the top card of that players library.
You may look at that cards and cast them for
as long as they remain exiled and you may
spend mana as though it were mana of any kind
to cast those cards.