Lullmage's Domination — ruling 1

To cast Lullmage's Domination, choose a value of X, choose a creature with the appropriate mana value, then determine the spell's cost, subtracting {3} if appropriate. This can't reduce the {U}{U}{U} in the spell's cost. For example, if you wish to target a creature with mana value 2 whose controller has eight cards in their graveyard, you'll pay {U}{U}{U}.

Lullmage's Domination — ruling 2

If a creature on the battlefield has {X} in its mana cost, X is considered to be 0.

Lullmage's Domination — ruling 3

Once Lullmage's Domination resolves, the control effect lasts until the creature leaves the battlefield or you lose the game. It doesn't expire at the end of turn.

Lullmage's Domination — ruling 4

An ability that offers a bonus if an opponent has eight or more cards in their graveyard won't provide additional benefits if more than one opponent has eight or more cards in their graveyard. There are also no additional benefits no matter how many cards are in an opponent's graveyard, as long as there are at least eight.

Lullmage's Domination — ruling 5

In a multiplayer game, once an opponent leaves the game, they won't be considered for such an effect, no matter how many cards they had in their graveyard before leaving the game.

Lullmage's Domination : règles, fonctionnement et interactions (MTG)

Lullmage's Domination 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

This spell costs less to cast if it targets a creature whose controller has eight or more cards in their graveyard. Gain control of target creature with mana value X.

How it works : Lullmage's Domination

Original English text — Wizards of the Coast / Scryfall

#1September 25, 2020· Wizards of the Coast
To cast Lullmage's Domination, choose a value of X, choose a creature with the appropriate mana value, then determine the spell's cost, subtracting if appropriate. This can't reduce the in the spell's cost. For example, if you wish to target a creature with mana value 2 whose controller has eight cards in their graveyard, you'll pay .
No other card is named in this ruling.
#2September 25, 2020· Wizards of the Coast
If a creature on the battlefield has in its mana cost, X is considered to be 0.
No other card is named in this ruling.
#3September 25, 2020· Wizards of the Coast
Once Lullmage's Domination resolves, the control effect lasts until the creature leaves the battlefield or you lose the game. It doesn't expire at the end of turn.
No other card is named in this ruling.
#4September 25, 2020· Wizards of the Coast
An ability that offers a bonus if an opponent has eight or more cards in their graveyard won't provide additional benefits if more than one opponent has eight or more cards in their graveyard. There are also no additional benefits no matter how many cards are in an opponent's graveyard, as long as there are at least eight.
No other card is named in this ruling.
#5September 25, 2020· Wizards of the Coast
In a multiplayer game, once an opponent leaves the game, they won't be considered for such an effect, no matter how many cards they had in their graveyard before leaving the game.
No other card is named in this ruling.