Cei

The Cei are an aquatic water thriving race. They have tentacles and are a large squid like alien. During a war between the Cei and a corrosponding planet the Cei were defeated but sent a Terraforming Device which takes the appearance of a large gold sphere. This device will turn Earth into an aquatic world and an outpost for the Cei. During The Runaway Drain the Doctor and his team encounter a Cei and one of their titanic spaceships.