Sidisi, Sultai Necromancer

{1}{u/b}{b/g}{g/u}: Exile target creature from a graveyard and then, create a token copy of that creature except its 4/4 and its a Black Zombie in addition to its other colors and types.
Whenever one or more Zombies you control attacks, send a card from the top of your library to the graveyard for each Zombie that attacked. Then, create a 2/2 Black Zombie creature token onto the battlefield tapped for each creature sent to the graveyard this way.