Mayael's Aria

Enchantment, RGW (3)
At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.
Illus. Steve Argyle

Gatherer Card Rulings [Nov 2009]

• 5/1/2009: This ability triggers at the beginning of each of your upkeeps. Whether you control any applicable creatures is checked only when the ability resolves.
• 5/1/2009: The three parts of the ability happen sequentially. For example, if you control a creature with 9 power when the ability starts to resolve, you'll put a +1/+1 counter on each creature you control -- and now, since you control a creature with 10 power, you'll gain 10 life.

Format Legality	Legal in Vintage, Legacy, Extended, Standard
Printings (1/9)	Alara Reborn (Rare)