Sphinx is a monument of a human headed lion portrayed as a symbol of the sun in Egypt mythology. Compared to Greek mythology, Sphinx is a female headed lion with breasts. As written in The Encyclopedia of Classical Mythology, Sphinx is also a soothsayer. The myth of the unsolved riddle and the associated plague forms part of the Oedipus legend, in which a Sphinx ravages the district round Thebes. Sphinx is also the Greek designation for the lioness with a queen’s head which is familiar from the Egyptian world.
In Harry Potter world, sphinx has two contrary values, virtue and evil. Sphinx is a symbol of the higher nature arising from the lower, or of the Spirit triumphant over matter. Primarily the Sphinx represented an imaginary quadruped, human headed, and supposed to be favorite incarnation assumed by the Sun God of Egypt, Ra, when he desired to protect his friends and adherents. The desire to protect is the keywords that reflect the virtue. It is portrayed almost as same as the Sphinx in Harry Potter world. The Sphinx tends to keep the Triwizard Cup for the best champion. Wizards also use Sphinx to keep their valuable properties or hidden places. Gringotts Wizarding Bank, a bank in the Harry Potter story is known to places Sphinxes to guard some of the vaults. In Roman philosophy, virtue associates with virility and strength character. Meanwhile, Carl Jung saw Sphinx as a symbol of the devouring mother.
Although, Sphinx has the desire to protect and wonderfully unique with the love of puzzle and riddle, Sphinx has also the evil side. That is the vicious character which can kill wizards, no matter who may be. Her wicked act, experience, and things are suitable with her scary looking claws. Her undesirable and harmful thing is on the possibility to be killed, if somebody just answers her question wrongly. In Western mythology, Sphinx is considered as a Greek demon of ruin and misfortune which capture people and kill them.
Source: Signs & Symbols by Mark O’Connel and Raje Airey; Dictionary of Philosophy by Dagobert D. Runes; Dictionary of All Scriptures & Myths by G.A. Gaskel; The Encyclopedia of Classical Mythology; The World Book Encyclopedia.