Matsya Purana — Narasimha’s Victory over Hiraṇyakaśipu and the Catalogue of Apocalyptic Omens
बाह्यतो ववृषुर्वर्षं नोपरिष्टाच्च ववृषुः मृगेन्द्रप्रतिरूपस्य स्थितस्य युधि मायया //
bāhyato vavṛṣurvarṣaṃ nopariṣṭācca vavṛṣuḥ mṛgendrapratirūpasya sthitasya yudhi māyayā //
By his māyā, while he stood in battle in the form of a lion, they poured down a rain only from the outer side—yet they did not shower it from above.
It highlights māyā—supernatural manipulation of natural forces (like rain)—a motif used in Puranic narration to show how cosmic powers can override ordinary causality, often echoed in Pralaya-themed storytelling.
Indirectly, it underscores discernment (viveka): leaders and householders are advised in Purāṇic ethics to judge appearances carefully, since deception and illusion can operate in conflict and public life.
No direct Vāstu or ritual rule is stated; the key takeaway is symbolic—control of directions (outside vs. above) and environmental forces, themes sometimes mirrored in later Vāstu discussions of orientation and protective measures.