Origin of Thor is a uncommon Enchantment — Saga card from Marvel Super Heroes Commander (MSC), collector number 701. Current market price: $0.30 (foil $1.68), TCGplayer market prices via Scryfall.
(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — You may discard a card. If you do, draw two cards. II — Whenever you cast a spell this turn, put a +1/+1 counter on target creature you control. III — Target creature you control deals damage equal to its power to each opponent.