Kozilek, the Great Distortion — ruling 1

Kozilek's triggered ability checks to see if you have fewer than seven cards in hand when you cast it. Kozilek is on the stack at this time and not in your hand. If you don't, the ability won't trigger at all. If the ability does trigger, it will check again as it tries to resolve. If you have seven or more cards in hand at that time, the ability won't do anything.

Kozilek, the Great Distortion — ruling 2

To activate the last ability, there must be a legal target: a spell on the stack. That target will determine the value of X and the mana value of the card you discard. You can't activate the ability unless you can match the mana value of a spell on the stack to that of a card in your hand.

Kozilek, the Great Distortion — ruling 3

The mana value of a spell doesn't change, even if it's been cast using an alternative cost (such as an awaken cost). For example, the mana value of a Sheer Drop (a spell with mana cost {2}{W}) that's been cast for its awaken cost of {5}{W} is 3.

Kozilek, the Great Distortion — ruling 4

If there's an {X} in the mana cost of the card you discard, that X is 0. Any {X} in the mana cost of the target spell will have whatever value was determined for it as the spell was cast.

Kozilek, the Great Distortion : règles, fonctionnement et interactions (MTG)

Kozilek, the Great Distortion 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

When you cast this spell, if you have fewer than seven cards in hand, draw cards equal to the difference. Menace Discard a card with mana value X: Counter target spell with mana value X.

Complete guide

Kozilek, the Great Distortion returns as a massive colorless threat that refuels your hand and controls the stack. As a legendary Eldrazi, it demands respect with its imposing presence and its ability to bend the game to your will.

A Handful of Power

When you cast Kozilek, the Great Distortion, you check your hand size. If you have fewer than seven cards, an ability triggers that will draw you enough cards to reach seven. Since this is a 'cast' trigger, you draw those cards before Kozilek even enters the battlefield. However, note that if you have seven or more cards in hand at the moment of casting or at the moment the ability resolves, you will not draw any cards.

Master of the Stack

Once on the battlefield, Kozilek allows you to discard a card to counter a spell, provided the mana values match exactly. To activate this, you must target a spell currently on the stack. The mana value of a spell is determined by its mana cost, regardless of any alternative costs paid. If the spell on the stack has an {X} in its cost, X is the value chosen as it was cast. Conversely, if you discard a card with {X} in its cost to pay for Kozilek's ability, that X is always treated as 0.

Combat and Protection

With Menace, Kozilek is difficult to block, requiring at least two creatures to stand in its way. This makes its 12/12 stats extremely dangerous. Combined with the ability to counter removal spells by matching their mana values, Kozilek can end a game quickly if not dealt with immediately by a coordinated defense.

Interaction examples

Refilling the Hand

Kozilek, Butcher of Truth

If you have two cards in hand and cast Kozilek, the Great Distortion, its trigger goes on the stack. Upon resolution, it checks your hand; since you have one card left (assuming you didn't play anything else), you draw six cards to reach seven. If you later cast Kozilek, Butcher of Truth, you simply draw four cards regardless of your hand size, showcasing the difference between the 'refill' mechanic and a flat draw effect.

Countering High-Value Spells

Summon: Bahamut

Suppose your opponent casts Summon: Bahamut, which has a mana value of 9. If you have another copy of Kozilek, the Great Distortion in your hand (which has a mana value of 10), you cannot discard it to counter the Saga. You must discard a card with a mana value of exactly 9. If you do possess a card with mana value 9, you discard it as a cost to activate Kozilek's ability, and Summon: Bahamut will be countered and put into its owner's graveyard.

Guide written with AI from the official text and rulings. Official English text prevails.

How it works : Kozilek, the Great Distortion

Original English text — Wizards of the Coast / Scryfall

#1January 22, 2016· Wizards of the Coast
Kozilek's triggered ability checks to see if you have fewer than seven cards in hand when you cast it. Kozilek is on the stack at this time and not in your hand. If you don't, the ability won't trigger at all. If the ability does trigger, it will check again as it tries to resolve. If you have seven or more cards in hand at that time, the ability won't do anything.
No other card is named in this ruling.
#2January 22, 2016· Wizards of the Coast
To activate the last ability, there must be a legal target: a spell on the stack. That target will determine the value of X and the mana value of the card you discard. You can't activate the ability unless you can match the mana value of a spell on the stack to that of a card in your hand.
No other card is named in this ruling.
#3January 22, 2016· Wizards of the Coast
The mana value of a spell doesn't change, even if it's been cast using an alternative cost (such as an awaken cost). For example, the mana value of a Sheer Drop (a spell with mana cost ) that's been cast for its awaken cost of is 3.
No other card is named in this ruling.
#4January 22, 2016· Wizards of the Coast
If there's an in the mana cost of the card you discard, that X is 0. Any in the mana cost of the target spell will have whatever value was determined for it as the spell was cast.
No other card is named in this ruling.