The Vanishing Masterpiece

Victor, a reclusive artist, discovers a mysterious painting in his late grandmother's attic and decides to sell it at a prestigious art gallery. The gallery's cunning dealer, Harold Sterling, recognizes the painting's immense value but decides to deceive Victor. Claiming he couldn't find a buyer, Harold hands Victor a package that turns out to contain only wrapping paper.  Realizing he's been cheated, Victor returns to the gallery, only to be confronted and threatened by Harold's henchmen.
In a fit of rage, Victor curses Harold and his men, unleashing a primal fury within himself. As a savage, werewolf-like hunter, Victor embarks on a deadly rampage across the city, killing each henchman in brutal fashion.