Vana Parva 203.14

Madhu and Kaitabha became greatly astonished on seeing the lotus-eyed Grandsire sitting on the lotus. They then began to terrify Brahma of immeasurable prowess. The illustrious Brahma, frightened by them, began to tremble on his seat. At his trembling, the stalk of the lotus began to tremble and thus Keshava awoke and he saw those two greatly effulgent Danavas.