Kraken

The Kraken was a creature that lived in the depths of Earth's seas.

With the downfall of Alexandria and the conjunction of Mars, Jupiter, and Saturn, the Kraken rose from the sea and destroyed the remnants of the city.

Under the effects of Voyager, the Sixth Doctor dreamt about the Kraken. (COMIC: Voyager) "The Kraken himself saluted our passage"

- Sixth Doctor

In 1805, the crew of a ship took their attacker to be the Kraken when in fact it was an aircraft carrier, taken back in time by an infestation of Time Roaches. The Eleventh Doctor claimed he had taken the real Kraken back home. (COMIC: Rough Waters)