The Final Finale

(You may cast a legendary sorcery only if you control
a legendary creature or planeswalker.)
Each player sacrifices any number, or X, lands.
Return up to X creatures and/or planeswalkers
from your exile and graveyard to the battlefield.
The citizens of Ravnica watched in horror as the Prison Realm portal reopened on the Gateway Plaza, spewing
out hundreds of terrors, including Bolas and his horns,
tearing apart the fabric of the Multiverse.