Undead Reunion

Return up to two creature cards from your
graveyard to the battlefield. They become Black
Zombies in addition to their other colours and
types and have base power and toughness 4/4.
Dredge 15 (If you would draw a card, instead you
may put exactly fifteen cards from the top of your
library into your graveyard. If you do, return this
card from your graveyard to your hand. Otherwise,
draw a card.)