When Chthonian Nightmare enters the battlefield, you get EEE (three energy counters).
Pay X E, Sacrifice a creature, Return Cthonian Nightmare to its owner's hand: Return target creature card with mana value X from your graveyard to the battlefield. Activate only as a sorcery.
NM-Mint Foil - $6.80
Lightly Played Foil - $6.50
Moderately Played Foil - $6.10
Heavily Played Foil - $5.50
Damaged Foil - $4.40
NM-Mint Foil Non English - $6.80
Lightly Played Foil Non English - $6.50
Moderately Played Foil Non English - $6.10
Heavily Played Foil Non English - $5.50
Damaged Foil Non English - $4.40