Serifos is one of possible areas inhabited by Cyclops in the cave close to Psaropyrgos.
Perseus, the son of Danae and Zeus lived here. Danae’s father, king of Argos, Acrisius, in response to an oracle that his own grandson would kill him, set Danae and the baby adrift at sea in a wooden chest. It was washed ashore in Serifos. Dyktis, the first king of Serifos, welcomed Danae and Perseus. But the second king of Serifos, Polydektes, fell in love with Danae and sent Perseus to kill Gorgon Medusa. Medusa was notorious for petrifying anyone who stared at her. Perseus killed her with the aid of the weapons of Gods, mainly with the shield of Athena that he used as a mirror to avoid looking directly in her eyes. Then he returned to Serifos, demonstrated the head of the Medusa and turned Polydektes and his retainers into stone. That is the reason why the island is so rocky.