What is "mandavya"

Mandavya was a sage, who according to Hinduism, was wrongly punished by the king by being impaled. This occurred as the chief of a band of robbers had hidden their stolen goods in a corner of his hermitage when he was in deep contemplation, and he was wrongly assumed to have stolen the goods. Lord Yama gave him this punishment for having tortured birds and bees in his childhood. In response, Mandavya cursed the Dharma, as his punishment exceeded the sins committed as an ignorant child. Therefore, he cursed him to be born in the mortal world. He was born as Vidura, the wise, to the servant maid of Ambalika, wife of King Vichitravirya, who offered her to Sage Vyasa in place of Ambalika. It is also considered in the mythological hinduism story that Mandavya rishi is a son of Manu and his name is manavya, later change into Mandavya. But In other Accounts Mandavya rishi have also pravaras of Rishi Chayavana, Jamadagni and Aapvan. Mandavya is a gotra in different castes.