Old World's Agony

This spell can't be countered.
Sacrifice X lands, where X is greater than 0.
This spell deals X damage to each creature on
the battlefield. For each one that dies by being
dealt damage this way you may search your
library for a land card and put it on the
battlefield tapped, then shuffle your library.
"You hear screams of this rotten world dying, yet I
hear an ode to the new one that is about to born!"
—Shandere, High Priest of Xagon