Bleh, another one I'm having trouble costing.

"Destroy four lands" is pretty much "Target player loses the game" Cost 6+.

Compare to Rain of Salt. Back in the crazy Urza Block, I used to run Magic tournaments. The deck that won week after week? A deck that featured 4x Rain of Salts. The guy would accelerate right into Rain of Salt by turn 3 and start sandblasting players out of the game.

Thankfully, acceleration isn't what it used to be during that crazy time. But it's still good. I'd say this card can't be cast for less than 8, to be honest. Even if your opponent is able to survive the first time this spell is cast, they will be incapable of playing the game if you throw a second copy on the table.

Yes, it's interesting that destroying one creature is usually more useful than destroying one land, but destroying 4 creatures, while very strong, is nowhere near as good as destroying 4 lands. Compare Hex.