Eldritch Evolution is a rare Sorcery card from Eldritch Moon (EMN), collector number 155. Current market price: $3.98 (foil $6.14), TCGplayer market prices via Scryfall.
As an additional cost to cast this spell, sacrifice a creature. Search your library for a creature card with mana value X or less, where X is 2 plus the sacrificed creature's mana value. Put that card onto the battlefield, then shuffle. Exile Eldritch Evolution.