Ghalta the Immovable — ruling 1

The first step of casting a spell is to move it to the stack. If this causes the greatest toughness of creatures you control to change (perhaps because you control a creature whose toughness is determined by the number of cards in your hand), that new toughness will be used to determine the cost reduction.

Ghalta the Immovable — ruling 2

Ghalta the Immovable's last ability doesn't actually change any creature's power. It changes only the amount of combat damage the creature assigns. All other rules and effects that check power or toughness use the real values, even if they cause damage "equal to a creature's power" to be dealt.

Ghalta the Immovable — ruling 3

Once you announce you're casting a spell, no player may take actions until the spell has been paid for. Notably, opponents can't try to reduce the toughness of creatures you control.

Ghalta the Immovable — ruling 4

Ghalta the Immovable's cost reduction ability can't reduce the total cost to cast the spell below {W}.

Ghalta the Immovable — ruling 5

Once you determine the cost to cast Ghalta the Immovable, you may activate mana abilities to pay that cost. If the greatest toughness of creatures you control changes while activating mana abilities, the cost to cast Ghalta remains what you previously determined.

Ghalta the Immovable — ruling 6

Ghalta the Immovable's mana value doesn't change no matter what the greatest toughness of creatures you control is.

Ghalta the Immovable : règles, fonctionnement et interactions (MTG)

Ghalta the Immovable 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, where X is the greatest toughness among creatures you control. Creatures you control can attack as though they didn't have defender. Each creature you control with toughness greater than its power assigns combat damage equal to its toughness rather than its power.

How it works : Ghalta the Immovable

Original English text — Wizards of the Coast / Scryfall

#1August 21, 2026· Wizards of the Coast
The first step of casting a spell is to move it to the stack. If this causes the greatest toughness of creatures you control to change (perhaps because you control a creature whose toughness is determined by the number of cards in your hand), that new toughness will be used to determine the cost reduction.
No other card is named in this ruling.
#2August 21, 2026· Wizards of the Coast
Ghalta the Immovable's last ability doesn't actually change any creature's power. It changes only the amount of combat damage the creature assigns. All other rules and effects that check power or toughness use the real values, even if they cause damage "equal to a creature's power" to be dealt.
No other card is named in this ruling.
#3August 21, 2026· Wizards of the Coast
Once you announce you're casting a spell, no player may take actions until the spell has been paid for. Notably, opponents can't try to reduce the toughness of creatures you control.
No other card is named in this ruling.
#4August 21, 2026· Wizards of the Coast
Ghalta the Immovable's cost reduction ability can't reduce the total cost to cast the spell below .
No other card is named in this ruling.
#5August 21, 2026· Wizards of the Coast
Once you determine the cost to cast Ghalta the Immovable, you may activate mana abilities to pay that cost. If the greatest toughness of creatures you control changes while activating mana abilities, the cost to cast Ghalta remains what you previously determined.
No other card is named in this ruling.
#6August 21, 2026· Wizards of the Coast
Ghalta the Immovable's mana value doesn't change no matter what the greatest toughness of creatures you control is.
No other card is named in this ruling.