The Winged Dragon of Ra

This spell can't be countered.
Flying
When the Winged Dragon of Ra enters the battlefield, pay any amount of life. The Winged
Dragon of Ra's power and toughness are each equal to the amount of life paid this way.
Blaze Cannon - At the beginning of your end step, destroy target nonland permanent you don't control with mana value X or less, where X is the amount
of life you gained this turn.