Acererak the Archlich (PAFR 87p)

Legendary Creature — Zombie Wizard • Mana cost: {2}{B} • Adventures in the Forgotten Realms Promos • Mythic

When Acererak enters, if you haven't completed Tomb of Annihilation, return Acererak to its owner's hand and venture into the dungeon.
Whenever Acererak attacks, for each opponent, you create a 2/2 black Zombie creature token unless that player sacrifices a creature of their choice.

Illustrated by Andrey Kuzinskiy.