Final answer:
The masked figure in Edgar Allan Poe's 'The Masque of the Red Death' is not Prospero's rival but represents the Red Death, making the statement false.
Step-by-step explanation:
The statement that the garments and mask of the corpse-like figure disguised Prospero's rival in "The Masque of the Red Death" is false. This short story by Edgar Allan Poe does not depict the masked figure as Prospero's rival, but rather as an embodiment of the Red Death itself, a personification of the plague that had been ravaging the land.
The mysterious figure appearing at Prince Prospero's masquerade ball is described as causing dread and horror among the guests due to its attire resembling the victim of the plague. The presence of this figure and the subsequent reaction of Prospero and his guests suggest themes of the inevitability of death and the futility of trying to escape it.