Saṃyutta Nikāya 4
Connected Discourses with Mara
Thus have I heard. On one occasion the Blessed One was dwelling at Rajagaha in the Bamboo Grove, the Squirrel Sanctuary. Now on that occasion the Blessed One was sitting out in the open in the thick darkness of the night while it was drizzling. Then Mara the Evil One … manifested himself in the form of a giant king serpent and approached the Blessed One. Its body was like a huge boat made from a single tree trunk; its hood, like a large brewer’s sieve; its eyes, like the large bronze dishes of Kosala; its tongue darting out from its mouth, like flashes of lightning emitted when the sky thunders; the sound of its breathing in and out, like the sound of a smith’s bellows filling with air.
Then Mara the Evil One … disappeared right there.