That part…

You may pay {B} rather than pay this spell’s mana cost if there are thirteen or more creatures on the battlefield. Each player sacrifices thirteen creatures of their choice.{flavor}{/bold}{/bold}”Check check check 1, 2, 1, 2(3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13) check check check check”