Vishnupurana 4.4.32

4.4.32

kālena gacchatā sa saudāso yajñam ayajat |
pariniṣṭhitayajñe cācārye vasiṣṭhe niṣkrānte tad rakṣo vasiṣṭharūpam āsthāya yajñāvasāne mama samāṃsaṃ bhojanaṃ deyaṃ tat saṃskriyatāṃ kṣaṇād ihāgamiṣyāmīty uktvā niṣkrāntaḥ ||

After some interval Saudása celebrated a sacrifice, which was conducted by Vaśisht́ha. At the close of the rite Vaśisht́ha went out; when the Rákshas, the fellow of the one that had been killed in the figure of a tiger, assumed the semblance of Vaśisht́ha, and came and said to the king, "Now that the sacrifice is ended, you must give me flesh to eat: let it be cooked, and I will presently return." Having said this, he withdrew, and, transforming himself into the shape of the cook, dressed some human flesh, which he brought to the king, who, receiving it on a plate of gold, awaited the reappearance of Vaśisht́ha. As soon as the Muni returned, the king offered to him the dish. Vaśisht́ha surprised at such want of propriety in the king, as his offering him meat to eat, considered what it should be that was so presented, and by the efficacy of his meditations discovered that it was human flesh. His mind being agitated with wrath, he denounced a curse upon the Rájá, saying, "Inasmuch as you have insulted all such holy men as we are, by giving me what is not to be eaten, your appetite shall henceforth be excited by similar food."