Origin of Black Widow is a uncommon Enchantment — Saga card from Marvel Super Heroes Commander (MSC), collector number 664. Current market price: $0.30 (foil $0.70), TCGplayer market prices via Scryfall.
(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Each opponent sacrifices a creature of their choice. II — Creatures you control gain deathtouch until end of turn. III — Each opponent loses 1 life for each creature card in their graveyard.