Answer
"The Phantom of the Opera" is not one of Sam Mendes' dark re-inventions of stage musicals because he has never directed the show. Mendes is known for his highly acclaimed and innovative interpretations of various musicals, but "The Phantom of the Opera" has not been among them. His notable directorial endeavors include "Cabaret," "Oliver!," and "Gypsy," each of which showcased his unique and bold approach to theatrical productions.