Introduction
Andhaka, "the blind one", is an Asura known chiefly through his death at the hands of Shiva, after he attempted to abduct Parvati. Several Puranas give him an unusual origin as a son of Shiva himself.
This article follows the Puranic tradition. Where a detail differs between texts, the article says so.
Origin
In one widely told account (in the Shiva and Matsya Puranas), Andhaka was born from a drop of Shiva's sweat, or from Shiva covering Parvati's eyes in play, and was blind and demonic in form. Displeased, Shiva gave the child to the Asura king Hiranyaksha (or in other versions, to another demon) to raise, and Andhaka grew up believing himself a full Asura, ignorant of his true parentage.
The attempt on Parvati
As an adult, Andhaka, not knowing she was his own mother, desired Parvati and attempted to take her by force. Shiva fought and killed him, in a fierce combat described at length in several Puranas, in which Andhaka's blood, wherever it fell, produced more demons like himself, until Shiva enlisted the goddess (as Yogeshvari or Kali) to drink the blood before it could touch the ground.
Redemption
In several tellings, Andhaka is not simply destroyed but transformed at the moment of death: recognising Shiva and Parvati as his true parents, he is granted devotion and a place among Shiva's attendants (Ganas), becoming known as Bhringi or a leader among them in some versions, rather than being annihilated outright.