Instead of a human head, the Hieracosphinx has the fierce head of a hawk, a nasty disposition and a razor-sharp beak – all the better to eviscerate those who cannot answer its riddles. It is a much more aggressive and pitiless Sphinx than its more peaceable cousins, the Criosphinx and Androsphinx.

“Say, sirrah, hast thou ever proved thyself a prophet? When the riddling Sphinx was here why hadst thou no deliverance for this folk?”

-- Oedipus, Oedipus Rex