Blasphemous Edict is a rare Sorcery card from Foundations Promos (PFDN), collector number 57p. Current market price: $4.23 (foil $4.59), TCGplayer market prices via Scryfall.
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.