The Tantra of Glorious Mahākāla
The Tantra of Glorious Mahākāla opens with Hayagrīva summoning Mahākāla from his abode in the palace called Joyous, located in a sandalwood grove in the great southeastern charnel ground, Aṭṭahāsa. This prompts the great king Virūpakṣa to request that Hayagrīva teach the rites and practices related to Mahākāla. Hayagrīva then delivers a series of instructions on the propitiation and worship of Mahākāla and rituals for destroying the enemies of the Buddhist teachings.