In the myth of Oedipus, the Sphinx is a creature with the head and chest of a woman, the body of a lion, and the wings of an eagle. It guards the entrance to the city of Thebes and asks all who pass a riddle. If they cannot answer the riddle, the Sphinx devours them.
One day, Oedipus comes to Thebes and is asked the riddle by the Sphinx. The riddle is: "What is the creature that walks on four legs in the morning, two legs at noon, and three legs in the evening?" Oedipus answers correctly that the creature is a man, who crawls on all fours as a baby, walks upright as an adult, and uses a cane in old age.
When Oedipus answers the riddle correctly, the Sphinx is so shocked that it throws itself from a cliff and dies. Oedipus is hailed as a hero and becomes the king of Thebes.