Izzet Keyrune — ruling 1

Until the ability that turns the Keyrune into a creature resolves, the Keyrune is colorless.

Izzet Keyrune — ruling 2

Activating the ability that turns the Keyrune into a creature while it’s already a creature will override any effects that set its power and/or toughness to another number, but effects that modify power and/or toughness without directly setting them will still apply.

Izzet Keyrune — ruling 3

If Izzet Keyrune becomes a creature in a way other than its own activated ability, its last ability will still work.

Izzet Keyrune : règles, fonctionnement et interactions (MTG)

Izzet Keyrune 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

: Add or . : Until end of turn, this artifact becomes a 2/1 blue and red Elemental artifact creature. Whenever this artifact deals combat damage to a player, you may draw a card. If you do, discard a card.

How it works : Izzet Keyrune

Original English text — Wizards of the Coast / Scryfall

#1April 15, 2013· Wizards of the Coast
Until the ability that turns the Keyrune into a creature resolves, the Keyrune is colorless.
No other card is named in this ruling.
#2April 15, 2013· Wizards of the Coast
Activating the ability that turns the Keyrune into a creature while it’s already a creature will override any effects that set its power and/or toughness to another number, but effects that modify power and/or toughness without directly setting them will still apply.
No other card is named in this ruling.
#3October 1, 2012· Wizards of the Coast
If Izzet Keyrune becomes a creature in a way other than its own activated ability, its last ability will still work.
No other card is named in this ruling.