Matsya Purana — Narasimha’s Victory over Hiraṇyakaśipu and the Catalogue of Apocalyptic Omens
समं समधिरोहन्तः सर्वे ते गगनेचराः शृङ्गाणि शनकैर्घोरा युगान्तावर्तिनो ग्रहाः //
samaṃ samadhirohantaḥ sarve te gaganecarāḥ śṛṅgāṇi śanakairghorā yugāntāvartino grahāḥ //
All those heavenly wanderers (the planets), moving in the sky, rise into an even alignment; terrifying, they slowly lift up their ‘horns’—for these are the grahas that turn and churn at the end of the age (yugānta).
It presents a pralaya-omen: the grahas become unnaturally aligned and appear fearsome, signaling the cosmic upheaval associated with yugānta (the end-phase leading into dissolution).
As a yugānta-portent passage, it implies vigilance toward dharma: rulers and householders should respond to ominous times with restraint, charity, ritual steadiness, and protection of dependents—core ethical responses emphasized in Purāṇic guidance during संकट (crisis).
No direct Vāstu rule is stated; the practical ritual takeaway is that abnormal graha behavior is treated as an inauspicious sign, traditionally prompting śānti (pacificatory) rites and careful timing (muhūrta) rather than new undertakings.