Mûreek, Arcane Coveter

Ward {2}
At the beginning of each opponent's end step,
that player reveals the top X cards of their
library, where X is the highest mana value
among spells they cast this turn. You may cast an
instant or sorcery spell from among cards
revealed this way, then put the rest on the
bottom of their owner's library in any order.
If you cast a spell this way, you lose X life. If you
don't, that player draws X cards.