Possible Clues:

• 'Riddling monster, half-woman, half-lion (6)'
• Giza statue
• Riddler of yore
• Inscrutable subject of Wilde
• Egyptian figure at Giza
• Riddle asker
• Mythological riddler
• It's worn in 27-Down
• Enigmatist jumping ship at New Cross?
• It posed riddle to Oedipus