Charybdis

"So we sailed on through the narrow straits, crying aloud for fear of Scylla on the one hand while divine Charybdis sucked the sea in terribly on the other. Whenever she spewed it out again, it bubbled and seethed in turmoil like a cauldron on a vast fire, and high overhead the spray rained down on the crags on either side. When she swallowed the seas, her inner vortex could be seen, and the rock echoed savagely round about, while below the seabed showed its dark-blue sand." (Homer, Odyssey, Book 12, lines 201–59)