Toadzilla Downfall of New York

This spell can't be countered.
When Toadzilla Downfall of New York enters the battlefield destroy up to 5 lands target opponent controls.
{x}Toadzilla Downfall of New York deals x amount of damage to target opponent.
{10}{w}{u}{b}{r}{g} All opponents take 20 damage.
{x}If x is equal to or more than 69 mana spent you win the game.