A son of Shiva and Parvati, worshiped only in Kerala.
In the Mahabharata, Arjuna went to Shiva to ask him for the Pashupata weapon. On the way he shot a boar. Then a hunter appeared who claimed to have shot the boar and that it therefore belonged to him. A dispute broke out until Arjuna realized that the hunter was Shiva. Shiva presents Pashupata to Arjuna.
In Kerala, Shiva is hunting with Parvati and the story goes on – after Arjuna left the couple stayed in the woods for a while, where Parvati gave birth to a son, Vettakkorumakan
Read about Vettakkorumakan here