Nibiru, Skyline Calamity

Split second
If an opponent cast five or more permanent
spells this turn, you may cast this spell from your
hand without paying its mana cost and as though
it had flash. If you do, choose a permanent type.
Target opponent sacrifices all permanents they
control of the chosen type that entered the battlefield this turn, then creates a colorless
Primal creature token with power and toughness
each equal to the number of permanents
sacrificed this way.