Kraken (Unnatural History)

The Kraken was a species that originated from a higher dimension. Kraken were big enough to flatten San Francisco. They could be found floating in the void where they twisted themselves through almost incomprehensible space. They were known to feed on exotic matter, plumes of raw cosmological power, as well as fountains of energy from the upper reaches which are undetectable in normal space. (EDA: Unnatural History)

The Kraken were one of the predators in the vortex, along with the Chronovores and the Swimmers. (EDA: The Shadows of Avalon)

In Earth mythology, the Kraken was an enormous octopus or squid. The Doctor claimed to have once encountered this creature and sent it back to it's home planet. (DWA: Rough Waters)