Chthonian Nightmare is a rare Enchantment card from Modern Horizons 3 (MH3), collector number 330. Current market price: $5.47 (foil $14.75), TCGplayer market prices via Scryfall.
When this enchantment enters, you get {E}{E}{E} (three energy counters). Pay X {E}, Sacrifice a creature, Return this enchantment to its owner's hand: Return target creature card with mana value X from your graveyard to the battlefield. Activate only as a sorcery.