Impending Doom is a uncommon Enchantment — Aura card from Theros Beyond Death (THB), collector number 139. Current market price: $0.10 (foil $0.25), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature gets +3/+3 and attacks each combat if able. When enchanted creature dies, this Aura deals 3 damage to that creature's controller.