Sphinx of the Final Word is a mythic Creature — Sphinx card from Oath of the Gatewatch (OGW), collector number 63. Current market price: $0.60 (foil $17.13), TCGplayer market prices via Scryfall.
This spell can't be countered. Flying Hexproof (This creature can't be the target of spells or abilities your opponents control.) Instant and sorcery spells you control can't be countered.