Revenge of the Rats is a uncommon Sorcery card from Foundations (FDN), collector number 67. Current market price: $0.30 (foil $0.38), TCGplayer market prices via Scryfall.
Create a tapped 1/1 black Rat creature token for each creature card in your graveyard. Flashback {2}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)