Holly Holtz, Grim Chirurgeon

When Holly Holtz, Grim Chirurgeon, enters the battlefield, create a 2/2 zombie horror creature
token for each creature that died this turn.
{u/b}{t}, sacrifice a creature: exhile the top three
cards from one player's library, face down. You
may look at the exiled card at any time, you may
cast it, and you may spend mana as though it
were mana of any type to cast that spell.
{b/r}{t}, sacrifice a creature: add {b}{b}{b} to
your mana pool.