Mukasura
Mukasura or Mukāsura (मुकासुर) was an "asura" in the Indian epic "Mahabharata". He was a friend of the Kauravas and the son of Upasunda, who was sent to disturb the austerities that Arjuna was performing at Indra keeladri, geographically now in Andhra pradesh. Mukasura went to the forest where Arjuna was practicing his vows of prayer, vigil, and fast and attacked Arjuna in the form of a boar. Arjuna was actually conducting his penance to please Siva and obtain the great weapon called "pasupatha-astra" (the missile of pasupatha, the lord of the animate world). Lord Siva sends Mukasara  in the form of a boar to test the severity of Arjuna's penances. He follows the boar in the guise of a hunter. Arjuna gets angry at the disturbing beast and shoots an arrow, while Siva simultaneously pierces it with an arrow of his own. A big argument over who has killed the boar follows, and a great fight ensues between Arjuna and Lord Siva. In the end, Siva appreciates the valour of Arjuna and grants hims the boon of the missile. Kiratarjuneeyam of Bharavi and a Telugu kavyam with the same name has the same storyline.