Skanda Purana — Brahma Khanda, Shloka 31
रक्षसा सूदरूपेण संमिश्रितनरामिषम् । शाकामिषं पुरः क्षिप्तं दृष्ट्वा गुरुरथाब्रवीत्
rakṣasā sūdarūpeṇa saṃmiśritanarāmiṣam | śākāmiṣaṃ puraḥ kṣiptaṃ dṛṣṭvā gururathābravīt
料理人に化けた羅刹（ラクシャサ）が、野菜料理に人肉を混ぜて彼の前に出した。それを見て、導師（グル）はこう言った。
Narrator (Purāṇic recounting; direct speech begins next verse)
Scene: A rakṣasa disguised as a cook presents a vegetable dish secretly mixed with human flesh; Vasiṣṭha perceives the impurity instantly; tension rises in a ritual meal setting.
FAQs
Ritual and hospitality become spiritually dangerous when polluted by deception; adharma hidden in offerings ripens into severe consequences.
No tīrtha is mentioned; the emphasis is on dharma regarding purity in śrāddha-like contexts and the peril of rākṣasa interference.
No explicit prescription; the verse implies the necessity of strict purity in food served to sages, especially on Pitṛ-related observance days.