Matsya Purana — Manifestation of Kauśikī
देव्या रूपधरो दैत्यो देवं वञ्चयितुं त्विह प्रविष्टो न च दृष्टो ऽसौ स वै देवेन घातितः //
devyā rūpadharo daityo devaṃ vañcayituṃ tviha praviṣṭo na ca dṛṣṭo 'sau sa vai devena ghātitaḥ //
A Daitya, assuming the very form of the Goddess, entered here intending to deceive the god; but he was recognized, and indeed that one was slain by the deity.
This verse does not address pralaya directly; it highlights a moral-epic motif in which deceptive disguise (māyā/vañcanā) fails before divine power and discernment.
It implies a dharmic guideline: rulers and householders should be vigilant against छल (deception) and judge by conduct and truth rather than appearances—upholding protection of the community and punishment of harmful imposture.
No direct Vāstu or ritual procedure is stated; the closest takeaway is ritual-ethical—impurity of intent (deceit) is condemned even when clothed in sacred appearance, a principle often applied in temple/service contexts.