Decree of Pain is a rare Sorcery card from Commander 2013 (C13), collector number 72. Current market price: $0.36, TCGplayer market prices via Scryfall.
Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way. Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.) When you cycle this card, all creatures get -2/-2 until end of turn.