Darth Sidious, Emperor

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