Dark Wings Bring Your Downfall is a common Ongoing Scheme card from Duskmourn: House of Horror Commander (DSC), collector number 332. Current market price: $0.46, TCGplayer market prices via Scryfall.
(An ongoing scheme remains face up until it's abandoned.) Whenever you attack, create a 5/5 black Demon creature token with flying that's tapped and attacking. At the beginning of each end step, if two or more creatures died under your control this turn, abandon this scheme.