Devibhagavatapurana 3.27.9

3.27.9

purā'ṣṭamyāṃ bhadrakālī dakṣayajñavināśinī |
prādurbhūtā mahāghorā yoginī koṭibhiḥ saha ||

In ancient times, on the eighth day, Bhadra Kâli Goddess, the destroyer of the sacrifice, started by Daksa, appeared on that day in hideous forms, surrounded by hundreds and lakhs of Yoginîs (one of a class of sixty goddesses or female attendants on Kâli). Therefore one should worship in particular on the eighth day with scents, garlands, and pastes and various offerings.