Meaning
The tyrant-king of the Shahnama from whose shoulders grew two serpents that had to be fed with human brains, overthrown after a thousand years by Faridun and chained in Mount Damavand.
Usage & notes
Zahhak is the archetype of monstrous, blood-feeding tyranny; his serpent-shoulders make him an image of an evil that devours its own people, finally broken by the just Faridun.