Matsya Purana 183.92

183.92

devadeva uvāca.
śrūyatāmasya he deva! kapālasya tu sambhavaḥ.
śataṃ varṣasahasrāṇāṃ tapastaptvā sudāruṇam.. 183.92 ..

After that, that stream of blood ran for a thousand Divine years Lord Viṣṇu said to Me ‘How such a skull was brought into existence Explain it to Me to drive away My doubts’ I replied, ‘Deva! hear about it In ancient times Brahmâ was endowed with Divine form after thousands of years asceticism and through His asceticism He got a fifth head shining like gold I cut it off in anger It follows Me wherever I go’—90-94