The Aeneid by Virgil Book 2 Page 16

priest of Neptue, as drawn by lot, was slaying a great bull at the wonted altars; and lo! from Tenedos, over the peaceful depths – I shudder as I speak – a pair of serpents with endless coils are breasting he sea and side by side making for the shore. Their bosoms rise amid he surge, and their crests, blood-red, overtop the waves; the rest of them skims the main behind and their huge backs curve in many a fold; we hear the noise as the water foams.

And now they were gaining the fields and, with blazing eyes suffused with blood and fire, were licking with quivering tongues their hissing mouths. Pale at the sight, we scatter. They in unswerving course make for Laocoön; and first each serpent enfolds in its embrace the small bodies of his two sons and with its fangs feeds upon the hapless limbs.