Matsya Purana — Narasimha’s Victory over Hiraṇyakaśipu and the Catalogue of Apocalyptic Omens
ये ग्रहाः सर्वलोकस्य क्षये प्रादुर्भवन्ति वै ते सर्वे गगने दृष्टा व्यचरन्त यथासुखम् //
ye grahāḥ sarvalokasya kṣaye prādurbhavanti vai te sarve gagane dṛṣṭā vyacaranta yathāsukham //
Those celestial bodies that indeed manifest at the time of the world’s dissolution—all of them were seen in the sky, moving about freely at will.
It describes a pralaya-omen: unusual manifestations of grahas (celestial bodies/astral forces) that appear and roam the sky freely, signaling cosmic breakdown and disorder.
As an omen-text, it implies that rulers and householders should heed cosmic portents, intensify dharmic conduct, and undertake protective rites when signs of widespread calamity appear.
No direct Vastu rule is stated; the ritual takeaway is the recognition of astral irregularities as triggers for śānti (pacificatory) observances and protective ceremonies.