One Arabian interpretation of the this Iranian mythological figure, says that Zahhak, the son of an Arab ruler, was easily influenced by Ahriman (an evil spirit). After killing his own father and gorging himself on feasts, Zahhak granted Ahriman whatever he wanted - and what Ahriman wanted was to kiss Zahhak's shoulders. Snakes then sprang from where his lips had touched and they could not be removed. These snakes had to have a daily diet of human brains or they would turn on Zahhak himself.
[Iranian mythology]