the Sphinx

What creature is it that walks on four legs in the morning, two legs when the sun is high and on three legs in the evening?

Yes, it stems from Greek Mythology, the tragedy of Oedipus, who is abandoned at birth by his royal parents, because of a prediction that one day he will kill his father and marry his mother.

As fate will have it he did just that, but in blissful ignorance of the facts. When he found out the extent of his sins, he blinded himself in an attempt to free his people of the devine punishement he brought upon them.