Urza [Vanguard Series] Urza's Saga Promos you create a colorless Treasure

you create a colorless Treasure artifact token with "{T}

Set: Wizards of the Coast Online Store Type: Creature — Angel Rarity: Rare Cost: {3}{W}{W} Flying (This creature can't be blocked except by creatures with flying or reach

Gaea forged her soldiers into self-wielding weapons that struck down all impurities

−6: Create a white Avatar creature token

but how could that be

Urza [Vanguard Series] Urza's Saga Promos you create a colorless TreasureSet: Vanguard Series Type: Vanguard Rarity: Rare Cost: {3}: Urza deals 1 damage to target creature or player. An artificer of unparalleled renown, Urza was a powerful cipher even before he was able to planeswalk. Seeing the world as a large, integrated machine is his greatest strength and weakness, enabling him to solve almost any problem but blinding him to his solutions' effects on others.