Nivix, Aerie of the Firemind is a uncommon Land card from Duel Decks: Izzet vs. Golgari (DDJ), collector number 36. Current market price: $0.25, TCGplayer market prices via Scryfall.
{T}: Add {C}. {2}{U}{R}, {T}: Exile the top card of your library. Until your next turn, you may cast it if it's an instant or sorcery spell.