Oracle

Legendary Artifact 

This spell costs X less to cast, where X is the greatest power among creatures you control.
T: Add GG. You gain 2 life.
Whenever a nontoken creature enters the battlefield under your control, put a +1/+1 counter on it and draw a card.

Tournooi-info

Legal in: Vintage, Legacy, Modern, Standard, Commander

Officiele rulings

10/4/2019
The first step of casting a spell is to move it to the stack. If this causes the greatest power among creatures you control to change, that new power will be used to determine the cost reduction.

10/4/2019
Once you determine the cost to cast The Great Henge, you may activate mana abilities to pay that cost. If the greatest power among creatures you control changes while activating mana abilities, the cost to cast The Great Henge remains what you previously determined.

10/4/2019
Once The Great Henge’s last ability has triggered, you’ll draw a card even if you can’t put a +1/+1 counter on the creature for some reason (most likely because it has left the battlefield).

10/4/2019
To determine the total cost of a spell, start with the mana cost or alternative cost you’re paying, add any cost increases, then apply any cost reductions. The converted mana cost of the spell remains unchanged, no matter what the total cost to cast it was.

10/4/2019
The cost reduction ability reduces only the generic mana in the relic’s cost. The colored mana must still be paid.

10/4/2019
Once you announce that you’re casting a spell, no player may take actions until the spell has been paid for. Notably, opponents can’t try to change by how much a relic’s cost is reduced.

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