Pashupatastra

The Pashupatastra (IAST: Pāśupatāstra, Sanskrit: पाशुपतास्त्र; the Pashupati, an epithet of Shiva) an astra, a celestial missile, affiliated to the Hindu deity Shiva, as well as Kali and Adi Parashakti, which can be discharged by the mind, the eyes, words, or a bow.

Following the advice of Krishna to undertake a tapasya to attain this divine weapon, Arjuna left his brothers for the performance of a penance.

[6] Arjuna soon regained consciousness and began to mentally worship Lord Shiva.

He then understood that the Kirata was Lord Shiva, and overwhelmed with joy, Arjuna fell at his feet.

I have been pleased with you and will grant you an irresistible weapon.Shiva, and his wife, Parvati, offered their darshana to Arjuna, and blessed him with the Pashupatastra.