Eldritch Evolution is a rare Sorcery card from Secret Lair Promo (SLP), collector number 5. Current market price: $10.11 (foil $46.27), 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.