Eliminate the Competition

Oracle Text

As an additional cost to cast this spell, sacrifice X creatures.

Destroy X target creatures.

Card Rulings

9/20/2016 Once you announce that you’re casting Eliminate the Competition, players can’t try to remove creatures you’d like to sacrifice.
9/20/2016 If you somehow cast Eliminate the Competition without paying its mana cost, you’ll still choose a value for X and sacrifice X creatures.