Skandapurana 7.20.35

7.20.35

rājñā kalmāṣapādena śakterbhakṣaṇe kiṃ kāraṇaṃ kimarthaṃ ca rājā rakṣasāviṣṭa iti vyāsakṛtajijñāsāśamanārtha puna- rvistareṇa saudāsopākhyānārambhaḥ . tatra viśvāmitrapreritena rakṣasā hṛtacetanena rājñā māṃsabhojanārthine guruputrāya śaktaye manuṣyamāṃsapariveṣaṇam . tadvijñāya kruddhena muninā rājñe puruṣādo ( rākṣaso) bhaviṣyasīti śāpadānam . mohitena ca rājñā 'tvāmeva prathamaṃ sabhrātṛkaṃ bhakṣayiṣyāmī'ti pratijñānam .

To appease the inquiry made by Vyāsa as to what was the reason for Śakti being devoured by King Kalmāṣapāda and why the king was possessed by a demon, the beginning of the narrative of Saudāsa [is recounted] once more in detail: There, by the king whose senses were deranged by a demon dispatched by Viśvāmitra, human flesh was served to Śakti, the son of his guru, who had requested a meal of meat. Discovering this, the enraged sage gave a curse to the king: 'You shall become a man-eater (a rākṣasa).' And the deluded king made a vow: 'I will devour you first along with your brothers!'