Gideon's Phalanx is a rare Instant card from Magic Origins (ORI), collector number 14. Current market price: $0.25 (foil $0.65), TCGplayer market prices via Scryfall.
Create four 2/2 white Knight creature tokens with vigilance. Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, creatures you control gain indestructible until end of turn.