This is Mahakali Dhyanam mantra taken from Devī Mahatmya . The Devi Mahatmya or Devi Mahatmyam is a Hindu philosophical text describing the Goddess, known as Mahadevi or Adishakti, as the supreme power and creator of the universe. It is part of the Markandeya Purana, and was composed in Sanskrit around 400-500 CE, with authorship attributed to the sage (Rishi) Markandeya. It consists of Chapters 74 to 86 (13 chapters) of the Markandeya Purana.
ॐ खड्गं चक्रगदेषुचापपरिघाञ्छूलं भुशुण्डीं शिरः
शङ्खं सन्दधतीं करैस्त्रिनयनां सर्वाङ्गभूषावृताम् ।
नीलाश्मद्युतिमास्यपाददशकां सेवे महाकालिकां
यामस्तौत्स्वपिते हरौ कमलजो हन्तुं मधुं कौटभम् ॥
Om khaḍgaṃ cakragadeṣucāpaparighāñchūlaṃ bhuśuṇḍīṃ śiraḥ
śaṅkhaṃ sandadhatīṃ karaistrinayanāṃ sarvāṅgabhūṣāvṛtām ।
nīlāśmadyutimāsyapādadaśakāṃ seve mahākālikāṃ
yāmastautsvapite harau kamalajo hantuṃ madhuṃ kauṭabham ॥
Om, holding a scimitar, disk, mace, arrows and bow, lance, club, a skull and a conch shell in Her ten hands. The three-eyed goddess, Her body covered with ornaments, Her countenance with the brilliance of blue diamonds, with ten limbs. I offer my service to Mahākāli, She who Brahma praised for protection from the demons Madhu and Kaitabha, when Vishnu was in sleep.
