How did the sphinx become a monster?

The Sphinx became a monster in Greek mythology due to a curse from the gods. Originally depicted as a benevolent creature, she transformed into a malevolent being after being sent to terrorize the city of Thebes. Her infamous riddle, which she posed to travelers, became a means to devour those who could not answer correctly, solidifying her status as a monster in the eyes of the people. Ultimately, she was defeated by Oedipus, who solved her riddle, leading to her demise.