Bestow {2}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.) Nighthowler and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.
NM-Mint Foil - $2.50
Lightly Played Foil - $2.30
Moderately Played Foil - $2.00
Heavily Played Foil - $1.80
Damaged Foil - $1.30
NM-Mint Foil Non English - $2.50
Lightly Played Foil Non English - $2.30
Moderately Played Foil Non English - $2.00
Heavily Played Foil Non English - $1.80
Damaged Foil Non English - $1.30