Open a sealed Magic booster pack, reveal the cards, and put all creature cards revealed this way onto the battlefield under your control. They're Zombies in addition to their other types. (Remove those cards from your deck before beginning a new game.)
You can use any unopened, official Magic booster pack, including promotional booster packs.
You own creatures put onto the battlefield this way. If they die, they’ll go to your graveyard. They can be returned to your hand, shuffled into your library, and so on.
You must put all the creature cards revealed this way onto the battlefield.