Necrotic Hex — ruling 1

Let's say everyone controls lots of creatures. As Necrotc Hex resolves, first the player whose turn it is (likely you) chooses which six creatures they'll sacrifice, then each other player in turn order does the same, knowing the choices of players before them. Then all creatures are sacrificed simultaneously. Finally, you'll create the six tapped Zombies.

Necrotic Hex — ruling 2

You'll create six tapped Zombies no matter how many creatures you sacrifice.

Necrotic Hex : règles, fonctionnement et interactions (MTG)

Necrotic Hex is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Each player sacrifices six creatures of their choice. You create six tapped 2/2 black Zombie creature tokens.

How it works : Necrotic Hex

Original English text — Wizards of the Coast / Scryfall

#1November 10, 2020· Wizards of the Coast
Let's say everyone controls lots of creatures. As Necrotc Hex resolves, first the player whose turn it is (likely you) chooses which six creatures they'll sacrifice, then each other player in turn order does the same, knowing the choices of players before them. Then all creatures are sacrificed simultaneously. Finally, you'll create the six tapped Zombies.
Card named in this ruling
Zombie
#2November 10, 2020· Wizards of the Coast
You'll create six tapped Zombies no matter how many creatures you sacrifice.
Card named in this ruling
Zombie