what did Oedipus feed his son??

I wonder if you are mixing up some details. My best guess would be the myth of the house of Atreus, who lived under a curse ever since Atreus's father Tantalus fed his own son to the gods. They then cursed his family, a curse that punished Orestes and family, whose story is detailed in another famous Greek trilogy, written by Aeschylus. But I'm not positive that's what you're asking either.