Empty the Laboratory
The trade this sorcery asks for is unusual in its symmetry: it converts Zombies you already control into Zombies pulled off the top of your library, one for one, but launders the swap through a reveal-until effect that dumps whatever nonmatching cards it turns over onto the bottom in random order. That structure rewards a decklist with high enough Zombie density that the digging stays cheap, and it thins out the top of your library on the way, so the cards it buries are ones you were not going to draw for a while anyway. The real leverage is that the Zombies you sacrifice do not need to matter as bodies: tokens work, dying triggers work, and the payoff scales with committing to the creature type rather than with individual card selection. It functions less as a board rebuilder than a board upgrader, spending expendable fodder to promote a spread of the tribe's heaviest hitters onto the battlefield at once. The creatures still enter with summoning sickness, so this is not a haste-enabled swing turn; it is a mid-game accrual, banking on the difference between the average sacrificed body and the top of a Zombie-heavy deck. The randomness on the miss is the honest cost, since a graveyard-based reanimator would let you name exactly what returns; this one makes you accept the library as it lies, which is why the effect wants breadth of quality rather than a single specific target.
