Mustafa the Dig Enthusiast

When Mustafa The Dig Enthusiast enters the
battlefield, exile {x} cards from the top of your
library. For each card exiled this way, you may
pay life equal to its mana value and put it into
your hand unless an opponent sacrifices a
permanent.
{t}, Sacrifice Mustafa The Dig Enthusiast:
Put target instant or sorcery card from
your graveyard on top of your library