Nexus
From Tardis Wiki, the free Doctor Who reference
The Nexus was a gestalt species from another dimension. It fed on giant space molluscs, which attracted it to Tokyo when it fell into the Doctor's dimension, confusing the city with a source of food. Raine Creevy, Sergeant Pete Wilson and the an incarnation of the Master posing as the Doctor went to investigate. The Master hypnotised it into moving to the Phillipine sea, tricking it into killing itself as it couldn't swim. (AUDIO: Dominion)
