Tectonic Chaos

If you paid 4. Roll a d6, then search your
library for that many lands and put them
onto the battlefield.
If you paid 8. Roll a d20, then search your
library for that many lands and put them onto
the battlefield. Then destroy all creatures.
If the result is 20 destroy all opponents
creatures instead. Then search your library for
all lands and put it onto the battlefield tapped.