Moan of the Unhallowed is a uncommon Sorcery card from Game Night: Free-for-All (GN3), collector number 57. Current market price: $0.14, TCGplayer market prices via Scryfall.
Create two 2/2 black Zombie creature tokens. Flashback {5}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)