M Gengar-EX #XY166 from XY Black Star Promos is a reverse holo promo card that currently sells for about $1,057 ungraded, with graded copies ranging from $748 at grade 7 to $2,250 at grade 10. TCGrader's AI has graded 14 copies of M Gengar-EX (XY Black Star Promos), averaging 7.5 overall. Only 14% scored 9 or higher, so genuinely mint copies of this card are scarce. A grade 10 copy sells for around $2,250, about 2.1× the $1,057 raw price, so high-grade copies are worth grading.